zulip/corporate/tests/test_stripe.py

import json
import operator
import os
import re
import sys
import typing
import uuid
from dataclasses import dataclass
from datetime import datetime, timedelta, timezone
from decimal import Decimal
from functools import wraps
from typing import (
    TYPE_CHECKING,
    Any,
    Callable,
    Dict,
    List,
    Mapping,
    Optional,
    Sequence,
    Tuple,
    TypeVar,
)
from unittest import mock
from unittest.mock import Mock, patch

import orjson
import responses
import stripe
import stripe.util
import time_machine
from django.conf import settings
from django.core import signing
from django.urls.resolvers import get_resolver
from django.utils.crypto import get_random_string
from django.utils.timezone import now as timezone_now
from typing_extensions import ParamSpec, override

from corporate.lib.analytics import get_realms_with_default_discount_dict
from corporate.lib.stripe import (
    DEFAULT_INVOICE_DAYS_UNTIL_DUE,
    MAX_INVOICED_LICENSES,
    MIN_INVOICED_LICENSES,
    STRIPE_API_VERSION,
    AuditLogEventType,
    BillingError,
    BillingSessionAuditLogEventError,
    InitialUpgradeRequest,
    InvalidBillingScheduleError,
    InvalidTierError,
    RealmBillingSession,
    RemoteRealmBillingSession,
    RemoteServerBillingSession,
    StripeCardError,
    SupportType,
    SupportViewRequest,
    add_months,
    catch_stripe_errors,
    compute_plan_parameters,
    customer_has_credit_card_as_default_payment_method,
    customer_has_last_n_invoices_open,
    do_change_remote_server_plan_type,
    do_deactivate_remote_server,
    downgrade_small_realms_behind_on_payments_as_needed,
    get_latest_seat_count,
    get_plan_renewal_or_end_date,
    get_price_per_license,
    invoice_plans_as_needed,
    is_free_trial_offer_enabled,
    is_realm_on_free_trial,
    next_month,
    sign_string,
    stripe_customer_has_credit_card_as_default_payment_method,
    stripe_get_customer,
    unsign_string,
)
from corporate.models import (
    Customer,
    CustomerPlan,
    Event,
    LicenseLedger,
    PaymentIntent,
    ZulipSponsorshipRequest,
    get_current_plan_by_customer,
    get_current_plan_by_realm,
    get_customer_by_realm,
)
from zerver.actions.create_realm import do_create_realm
from zerver.actions.create_user import (
    do_activate_mirror_dummy_user,
    do_create_user,
    do_reactivate_user,
)
from zerver.actions.realm_settings import do_deactivate_realm, do_reactivate_realm
from zerver.actions.users import do_deactivate_user
from zerver.lib.test_classes import ZulipTestCase
from zerver.lib.timestamp import datetime_to_timestamp, timestamp_to_datetime
from zerver.lib.utils import assert_is_not_none
from zerver.models import (
    Message,
    Realm,
    RealmAuditLog,
    Recipient,
    UserProfile,
    get_realm,
    get_system_bot,
)
from zilencer.lib.remote_counts import MissingDataError
from zilencer.models import (
    RemoteRealm,
    RemoteRealmAuditLog,
    RemoteZulipServer,
    RemoteZulipServerAuditLog,
)

if TYPE_CHECKING:
    from django.test.client import _MonkeyPatchedWSGIResponse as TestHttpResponse

CallableT = TypeVar("CallableT", bound=Callable[..., Any])
ParamT = ParamSpec("ParamT")
ReturnT = TypeVar("ReturnT")

STRIPE_FIXTURES_DIR = "corporate/tests/stripe_fixtures"


def stripe_fixture_path(
    decorated_function_name: str, mocked_function_name: str, call_count: int
) -> str:
    # Make the eventual filename a bit shorter, and also we conventionally
    # use test_* for the python test files
    if decorated_function_name[:5] == "test_":
        decorated_function_name = decorated_function_name[5:]
    return f"{STRIPE_FIXTURES_DIR}/{decorated_function_name}--{mocked_function_name[7:]}.{call_count}.json"


def fixture_files_for_function(decorated_function: CallableT) -> List[str]:  # nocoverage
    decorated_function_name = decorated_function.__name__
    if decorated_function_name[:5] == "test_":
        decorated_function_name = decorated_function_name[5:]
    return sorted(
        f"{STRIPE_FIXTURES_DIR}/{f}"
        for f in os.listdir(STRIPE_FIXTURES_DIR)
        if f.startswith(decorated_function_name + "--")
    )


def generate_and_save_stripe_fixture(
    decorated_function_name: str, mocked_function_name: str, mocked_function: CallableT
) -> Callable[[Any, Any], Any]:  # nocoverage
    def _generate_and_save_stripe_fixture(*args: Any, **kwargs: Any) -> Any:
        # Note that mock is not the same as mocked_function, even though their
        # definitions look the same
        mock = operator.attrgetter(mocked_function_name)(sys.modules[__name__])
        fixture_path = stripe_fixture_path(
            decorated_function_name, mocked_function_name, mock.call_count
        )
        try:
            with responses.RequestsMock() as request_mock:
                request_mock.add_passthru("https://api.stripe.com")
                # Talk to Stripe
                stripe_object = mocked_function(*args, **kwargs)
        except stripe.error.StripeError as e:
            with open(fixture_path, "w") as f:
                assert e.headers is not None
                error_dict = {**vars(e), "headers": dict(e.headers)}
                f.write(
                    json.dumps(error_dict, indent=2, separators=(",", ": "), sort_keys=True) + "\n"
                )
            raise
        with open(fixture_path, "w") as f:
            if stripe_object is not None:
                f.write(str(stripe_object) + "\n")
            else:
                f.write("{}\n")
        return stripe_object

    return _generate_and_save_stripe_fixture


def read_stripe_fixture(
    decorated_function_name: str, mocked_function_name: str
) -> Callable[[Any, Any], Any]:
    def _read_stripe_fixture(*args: Any, **kwargs: Any) -> Any:
        mock = operator.attrgetter(mocked_function_name)(sys.modules[__name__])
        fixture_path = stripe_fixture_path(
            decorated_function_name, mocked_function_name, mock.call_count
        )
        with open(fixture_path, "rb") as f:
            fixture = orjson.loads(f.read())
        # Check for StripeError fixtures
        if "json_body" in fixture:
            requester = stripe.api_requestor.APIRequestor()
            # This function will raise the relevant StripeError according to the fixture
            requester.interpret_response(
                fixture["http_body"], fixture["http_status"], fixture["headers"]
            )
        return stripe.util.convert_to_stripe_object(fixture)

    return _read_stripe_fixture


def delete_fixture_data(decorated_function: CallableT) -> None:  # nocoverage
    for fixture_file in fixture_files_for_function(decorated_function):
        os.remove(fixture_file)


def normalize_fixture_data(
    decorated_function: CallableT, tested_timestamp_fields: Sequence[str] = []
) -> None:  # nocoverage
    # stripe ids are all of the form cus_D7OT2jf5YAtZQ2
    id_lengths = [
        ("test", 12),
        ("cus", 14),
        ("prod", 14),
        ("req", 14),
        ("si", 14),
        ("sli", 14),
        ("sub", 14),
        ("acct", 16),
        ("card", 24),
        ("ch", 24),
        ("ii", 24),
        ("il", 24),
        ("in", 24),
        ("pi", 24),
        ("price", 24),
        ("src", 24),
        ("src_client_secret", 24),
        ("tok", 24),
        ("txn", 24),
        ("invst", 26),
        ("rcpt", 31),
    ]
    # We'll replace cus_D7OT2jf5YAtZQ2 with something like cus_NORMALIZED0001
    pattern_translations = {
        f"{prefix}_[A-Za-z0-9]{{{length}}}": f"{prefix}_NORMALIZED%0{length - 10}d"
        for prefix, length in id_lengths
    }
    # We'll replace "invoice_prefix": "A35BC4Q" with something like "invoice_prefix": "NORMA01"
    pattern_translations.update(
        {
            '"invoice_prefix": "([A-Za-z0-9]{7,8})"': "NORMA%02d",
            '"fingerprint": "([A-Za-z0-9]{16})"': "NORMALIZED%06d",
            '"number": "([A-Za-z0-9]{7,8}-[A-Za-z0-9]{4})"': "NORMALI-%04d",
            '"address": "([A-Za-z0-9]{9}-test_[A-Za-z0-9]{12})"': "000000000-test_NORMALIZED%02d",
            # Don't use (..) notation, since the matched strings may be small integers that will also match
            # elsewhere in the file
            '"realm_id": "[0-9]+"': '"realm_id": "%d"',
            r'"account_name": "[\w\s]+"': '"account_name": "NORMALIZED-%d"',
        }
    )
    # Normalizing across all timestamps still causes a lot of variance run to run, which is
    # why we're doing something a bit more complicated
    for i, timestamp_field in enumerate(tested_timestamp_fields):
        # Don't use (..) notation, since the matched timestamp can easily appear in other fields
        pattern_translations[
            f'"{timestamp_field}": 1[5-9][0-9]{{8}}(?![0-9-])'
        ] = f'"{timestamp_field}": 1{i+1:02}%07d'

    normalized_values: Dict[str, Dict[str, str]] = {pattern: {} for pattern in pattern_translations}
    for fixture_file in fixture_files_for_function(decorated_function):
        with open(fixture_file) as f:
            file_content = f.read()
        for pattern, translation in pattern_translations.items():
            for match in re.findall(pattern, file_content):
                if match not in normalized_values[pattern]:
                    normalized_values[pattern][match] = translation % (
                        len(normalized_values[pattern]) + 1,
                    )
                file_content = file_content.replace(match, normalized_values[pattern][match])
        file_content = re.sub(r'(?<="risk_score": )(\d+)', "0", file_content)
        file_content = re.sub(r'(?<="times_redeemed": )(\d+)', "0", file_content)
        file_content = re.sub(
            r'(?<="idempotency-key": )"([0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f-]*)"',
            '"00000000-0000-0000-0000-000000000000"',
            file_content,
        )
        # Dates
        file_content = re.sub(r'(?<="Date": )"(.* GMT)"', '"NORMALIZED DATETIME"', file_content)
        file_content = re.sub(r"[0-3]\d [A-Z][a-z]{2} 20[1-2]\d", "NORMALIZED DATE", file_content)
        # IP addresses
        file_content = re.sub(r'"\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}"', '"0.0.0.0"', file_content)
        # All timestamps not in tested_timestamp_fields
        file_content = re.sub(r": (1[5-9][0-9]{8})(?![0-9-])", ": 1000000000", file_content)

        with open(fixture_file, "w") as f:
            f.write(file_content)


MOCKED_STRIPE_FUNCTION_NAMES = [
    f"stripe.{name}"
    for name in [
        "checkout.Session.create",
        "checkout.Session.list",
        "Charge.create",
        "Charge.list",
        "Coupon.create",
        "Customer.create",
        "Customer.create_balance_transaction",
        "Customer.list_balance_transactions",
        "Customer.retrieve",
        "Customer.save",
        "Customer.list",
        "Customer.modify",
        "Event.list",
        "Invoice.create",
        "Invoice.finalize_invoice",
        "Invoice.list",
        "Invoice.pay",
        "Invoice.refresh",
        "Invoice.upcoming",
        "Invoice.void_invoice",
        "InvoiceItem.create",
        "InvoiceItem.list",
        "PaymentIntent.confirm",
        "PaymentIntent.create",
        "PaymentIntent.list",
        "PaymentIntent.retrieve",
        "PaymentMethod.attach",
        "PaymentMethod.create",
        "PaymentMethod.detach",
        "PaymentMethod.list",
        "Plan.create",
        "Product.create",
        "SetupIntent.create",
        "SetupIntent.list",
        "SetupIntent.retrieve",
        "Subscription.create",
        "Subscription.delete",
        "Subscription.retrieve",
        "Subscription.save",
        "Token.create",
    ]
]


def mock_stripe(
    tested_timestamp_fields: Sequence[str] = [], generate: bool = settings.GENERATE_STRIPE_FIXTURES
) -> Callable[[Callable[ParamT, ReturnT]], Callable[ParamT, ReturnT]]:
    def _mock_stripe(decorated_function: Callable[ParamT, ReturnT]) -> Callable[ParamT, ReturnT]:
        generate_fixture = generate
        if generate_fixture:  # nocoverage
            assert stripe.api_key
        for mocked_function_name in MOCKED_STRIPE_FUNCTION_NAMES:
            mocked_function = operator.attrgetter(mocked_function_name)(sys.modules[__name__])
            if generate_fixture:
                side_effect = generate_and_save_stripe_fixture(
                    decorated_function.__name__, mocked_function_name, mocked_function
                )  # nocoverage
            else:
                side_effect = read_stripe_fixture(decorated_function.__name__, mocked_function_name)
            decorated_function = patch(
                mocked_function_name,
                side_effect=side_effect,
                autospec=mocked_function_name.endswith(".refresh"),
            )(decorated_function)

        @wraps(decorated_function)
        def wrapped(*args: ParamT.args, **kwargs: ParamT.kwargs) -> ReturnT:
            if generate_fixture:  # nocoverage
                delete_fixture_data(decorated_function)
                val = decorated_function(*args, **kwargs)
                normalize_fixture_data(decorated_function, tested_timestamp_fields)
                return val
            else:
                return decorated_function(*args, **kwargs)

        return wrapped

    return _mock_stripe


class StripeTestCase(ZulipTestCase):
    @override
    def setUp(self) -> None:
        super().setUp()
        realm = get_realm("zulip")

        # Explicitly limit our active users to 6 regular users,
        # to make seat_count less prone to changes in our test data.
        # We also keep a guest user and a bot to make the data
        # slightly realistic.
        active_emails = [
            self.example_email("AARON"),
            self.example_email("cordelia"),
            self.example_email("hamlet"),
            self.example_email("iago"),
            self.example_email("othello"),
            self.example_email("desdemona"),
            self.example_email("polonius"),  # guest
            self.example_email("default_bot"),  # bot
        ]

        # Deactivate all users in our realm that aren't in our whitelist.
        for user_profile in UserProfile.objects.filter(realm_id=realm.id).exclude(
            delivery_email__in=active_emails
        ):
            do_deactivate_user(user_profile, acting_user=None)

        # sanity check our 8 expected users are active
        self.assertEqual(
            UserProfile.objects.filter(realm=realm, is_active=True).count(),
            8,
        )

        # Make sure we have active users outside our realm (to make
        # sure relevant queries restrict on realm).
        self.assertEqual(
            UserProfile.objects.exclude(realm=realm).filter(is_active=True).count(),
            10,
        )

        # Our seat count excludes our guest user and bot, and
        # we want this to be predictable for certain tests with
        # arithmetic calculations.
        self.assertEqual(get_latest_seat_count(realm), 6)
        self.seat_count = 6
        self.signed_seat_count, self.salt = sign_string(str(self.seat_count))
        # Choosing dates with corresponding timestamps below 1500000000 so that they are
        # not caught by our timestamp normalization regex in normalize_fixture_data
        self.now = datetime(2012, 1, 2, 3, 4, 5, tzinfo=timezone.utc)
        self.next_month = datetime(2012, 2, 2, 3, 4, 5, tzinfo=timezone.utc)
        self.next_year = datetime(2013, 1, 2, 3, 4, 5, tzinfo=timezone.utc)

        # Make hamlet billing admin for testing.
        hamlet = self.example_user("hamlet")
        hamlet.is_billing_admin = True
        hamlet.save(update_fields=["is_billing_admin"])

    def get_signed_seat_count_from_response(self, response: "TestHttpResponse") -> Optional[str]:
        match = re.search(r"name=\"signed_seat_count\" value=\"(.+)\"", response.content.decode())
        return match.group(1) if match else None

    def get_salt_from_response(self, response: "TestHttpResponse") -> Optional[str]:
        match = re.search(r"name=\"salt\" value=\"(\w+)\"", response.content.decode())
        return match.group(1) if match else None

    def get_test_card_string(
        self,
        attaches_to_customer: bool,
        charge_succeeds: Optional[bool] = None,
        card_provider: Optional[str] = None,
    ) -> str:
        if attaches_to_customer:
            assert charge_succeeds is not None
            if charge_succeeds:
                if card_provider == "visa":
                    return "pm_card_visa"
                if card_provider == "mastercard":
                    return "pm_card_mastercard"
                raise AssertionError("Unreachable code path")
            else:
                return "pm_card_chargeCustomerFail"
        else:
            return "pm_card_visa_chargeDeclined"

    def assert_details_of_valid_session_from_event_status_endpoint(
        self, stripe_session_id: str, expected_details: Dict[str, Any]
    ) -> None:
        json_response = self.client_get(
            "/json/billing/event/status",
            {
                "stripe_session_id": stripe_session_id,
            },
        )
        response_dict = self.assert_json_success(json_response)
        self.assertEqual(response_dict["session"], expected_details)

    def assert_details_of_valid_payment_intent_from_event_status_endpoint(
        self,
        stripe_payment_intent_id: str,
        expected_details: Dict[str, Any],
    ) -> None:
        json_response = self.client_get(
            "/json/billing/event/status",
            {
                "stripe_payment_intent_id": stripe_payment_intent_id,
            },
        )
        response_dict = self.assert_json_success(json_response)
        self.assertEqual(response_dict["payment_intent"], expected_details)

    def trigger_stripe_checkout_session_completed_webhook(
        self,
        payment_method: str,
        stripe_session: Optional[stripe.checkout.Session] = None,
    ) -> None:
        [checkout_setup_intent] = iter(stripe.SetupIntent.list(limit=1))
        stripe_setup_intent = stripe.SetupIntent.create(
            payment_method=payment_method,
            confirm=True,
            payment_method_types=checkout_setup_intent.payment_method_types,
            customer=checkout_setup_intent.customer,
            metadata=checkout_setup_intent.metadata,
            usage=checkout_setup_intent.usage,
        )
        if stripe_session is None:
            [stripe_session] = iter(stripe.checkout.Session.list(limit=1))
        stripe_session_dict = stripe_session.to_dict_recursive()
        stripe_session_dict["setup_intent"] = stripe_setup_intent.id

        event_payload = {
            "id": f"evt_{get_random_string(24)}",
            "object": "event",
            "data": {"object": stripe_session_dict},
            "type": "checkout.session.completed",
            "api_version": STRIPE_API_VERSION,
        }

        response = self.client_post(
            "/stripe/webhook/", event_payload, content_type="application/json"
        )
        assert response.status_code == 200

    def send_stripe_webhook_event(self, event: stripe.Event) -> None:
        response = self.client_post(
            "/stripe/webhook/", event.to_dict_recursive(), content_type="application/json"
        )
        assert response.status_code == 200

    def send_stripe_webhook_events(self, most_recent_event: stripe.Event) -> None:
        while True:
            events_old_to_new = list(reversed(stripe.Event.list(ending_before=most_recent_event)))
            if len(events_old_to_new) == 0:
                break
            for event in events_old_to_new:
                self.send_stripe_webhook_event(event)
            most_recent_event = events_old_to_new[-1]

    def add_card_to_customer_for_upgrade(self, charge_succeeds: bool = True) -> None:
        start_session_json_response = self.client_post(
            "/json/upgrade/session/start_card_update_session"
        )
        response_dict = self.assert_json_success(start_session_json_response)
        self.assert_details_of_valid_session_from_event_status_endpoint(
            response_dict["stripe_session_id"],
            {
                "type": "card_update_from_upgrade_page",
                "status": "created",
                "is_manual_license_management_upgrade_session": False,
            },
        )
        self.trigger_stripe_checkout_session_completed_webhook(
            self.get_test_card_string(
                attaches_to_customer=True,
                charge_succeeds=charge_succeeds,
                card_provider="visa",
            )
        )
        response_dict = self.assert_json_success(start_session_json_response)
        self.assert_details_of_valid_session_from_event_status_endpoint(
            response_dict["stripe_session_id"],
            {
                "type": "card_update_from_upgrade_page",
                "status": "completed",
                "is_manual_license_management_upgrade_session": False,
                "event_handler": {"status": "succeeded"},
            },
        )

    def upgrade(
        self,
        invoice: bool = False,
        talk_to_stripe: bool = True,
        upgrade_page_response: Optional["TestHttpResponse"] = None,
        del_args: Sequence[str] = [],
        dont_confirm_payment: bool = False,
        **kwargs: Any,
    ) -> "TestHttpResponse":
        if upgrade_page_response is None:
            upgrade_page_response = self.client_get("/upgrade/", {})
        params: Dict[str, Any] = {
            "schedule": "annual",
            "signed_seat_count": self.get_signed_seat_count_from_response(upgrade_page_response),
            "salt": self.get_salt_from_response(upgrade_page_response),
        }
        if invoice:  # send_invoice
            params.update(
                billing_modality="send_invoice",
                licenses=kwargs.get("licenses", 123),
            )
        else:  # charge_automatically
            params.update(
                billing_modality="charge_automatically",
                license_management="automatic",
            )

        params.update(kwargs)
        for key in del_args:
            if key in params:
                del params[key]

        if talk_to_stripe:
            [last_event] = iter(stripe.Event.list(limit=1))

        upgrade_json_response = self.client_post("/json/billing/upgrade", params)

        if upgrade_json_response.status_code != 200 or dont_confirm_payment:
            # Return early if the upgrade request failed.
            return upgrade_json_response

        if invoice or not talk_to_stripe or is_free_trial_offer_enabled():
            # Upgrade already happened for free trial or invoice realms.
            return upgrade_json_response

        last_stripe_payment_intent = PaymentIntent.objects.last()
        assert last_stripe_payment_intent is not None

        response_dict = self.assert_json_success(upgrade_json_response)
        self.assertEqual(
            response_dict["stripe_payment_intent_id"],
            last_stripe_payment_intent.stripe_payment_intent_id,
        )

        # Verify that the payment was successful.
        self.assert_details_of_valid_payment_intent_from_event_status_endpoint(
            last_stripe_payment_intent.stripe_payment_intent_id,
            {"status": "succeeded"},
        )

        # Upgrade the organization.
        self.send_stripe_webhook_events(last_event)
        return upgrade_json_response

    def add_card_and_upgrade(self, user: UserProfile, **kwargs: Any) -> stripe.Customer:
        # Add card
        with time_machine.travel(self.now, tick=False):
            self.add_card_to_customer_for_upgrade()

        # Check that we correctly created a Customer object in Stripe
        stripe_customer = stripe_get_customer(
            assert_is_not_none(Customer.objects.get(realm=user.realm).stripe_customer_id)
        )
        self.assertTrue(stripe_customer_has_credit_card_as_default_payment_method(stripe_customer))

        with time_machine.travel(self.now, tick=False):
            response = self.upgrade(**kwargs)
        self.assert_json_success(response)

        return stripe_customer

    # Upgrade without talking to Stripe
    def local_upgrade(
        self,
        licenses: int,
        automanage_licenses: bool,
        billing_schedule: int,
        charge_automatically: bool,
        free_trial: bool,
    ) -> None:
        class StripeMock(Mock):
            def __init__(self, depth: int = 1) -> None:
                super().__init__(spec=stripe.Card)
                self.id = "cus_123"
                self.created = "1000"
                self.last4 = "4242"

        def upgrade_func(
            licenses: int,
            automanage_licenses: bool,
            billing_schedule: int,
            charge_automatically: bool,
            free_trial: bool,
            *mock_args: Any,
        ) -> Any:
            hamlet = self.example_user("hamlet")
            billing_session = RealmBillingSession(hamlet)
            return billing_session.process_initial_upgrade(
                CustomerPlan.TIER_CLOUD_STANDARD,
                licenses,
                automanage_licenses,
                billing_schedule,
                charge_automatically,
                free_trial,
            )

        for mocked_function_name in MOCKED_STRIPE_FUNCTION_NAMES:
            upgrade_func = patch(mocked_function_name, return_value=StripeMock())(upgrade_func)
        upgrade_func(
            licenses, automanage_licenses, billing_schedule, charge_automatically, free_trial
        )

    def setup_mocked_stripe(self, callback: Callable[..., Any], *args: Any, **kwargs: Any) -> Mock:
        with patch.multiple("stripe", Invoice=mock.DEFAULT, InvoiceItem=mock.DEFAULT) as mocked:
            mocked["Invoice"].create.return_value = None
            mocked["Invoice"].finalize_invoice.return_value = None
            mocked["InvoiceItem"].create.return_value = None
            callback(*args, **kwargs)
            return mocked


class StripeTest(StripeTestCase):
    def test_catch_stripe_errors(self) -> None:
        @catch_stripe_errors
        def raise_invalid_request_error() -> None:
            raise stripe.error.InvalidRequestError("message", "param", "code", json_body={})

        with self.assertLogs("corporate.stripe", "ERROR") as error_log:
            with self.assertRaises(BillingError) as billing_context:
                raise_invalid_request_error()
            self.assertEqual("other stripe error", billing_context.exception.error_description)
            self.assertEqual(
                error_log.output, ["ERROR:corporate.stripe:Stripe error: None None None None"]
            )

        @catch_stripe_errors
        def raise_card_error() -> None:
            error_message = "The card number is not a valid credit card number."
            json_body = {"error": {"message": error_message}}
            raise stripe.error.CardError(
                error_message, "number", "invalid_number", json_body=json_body
            )

        with self.assertLogs("corporate.stripe", "INFO") as info_log:
            with self.assertRaises(StripeCardError) as card_context:
                raise_card_error()
            self.assertIn("not a valid credit card", str(card_context.exception))
            self.assertEqual("card error", card_context.exception.error_description)
            self.assertEqual(
                info_log.output, ["INFO:corporate.stripe:Stripe card error: None None None None"]
            )

    def test_billing_not_enabled(self) -> None:
        iago = self.example_user("iago")
        with self.settings(BILLING_ENABLED=False):
            self.login_user(iago)
            response = self.client_get("/upgrade/", follow=True)
            self.assertEqual(response.status_code, 404)

    @mock_stripe(tested_timestamp_fields=["created"])
    def test_upgrade_by_card(self, *mocks: Mock) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)
        response = self.client_get("/upgrade/")
        self.assert_in_success_response(["Your subscription will renew automatically"], response)
        self.assertNotEqual(user.realm.plan_type, Realm.PLAN_TYPE_STANDARD)
        # This also means there is no card set as default payment method set for the user.
        self.assertFalse(Customer.objects.filter(realm=user.realm).exists())

        # Click "Purchase Zulip Cloud Standard" without adding a card.
        with self.assertLogs("corporate.stripe", "WARNING"):
            response = self.upgrade()
        self.assert_json_error(response, "Please add a credit card before upgrading.")

        stripe_customer = self.add_card_and_upgrade(user)

        self.assertEqual(stripe_customer.description, "zulip (Zulip Dev)")
        self.assertEqual(stripe_customer.discount, None)
        self.assertEqual(stripe_customer.email, user.delivery_email)
        assert stripe_customer.metadata is not None
        metadata_dict = dict(stripe_customer.metadata)
        self.assertEqual(metadata_dict["realm_str"], "zulip")
        try:
            int(metadata_dict["realm_id"])
        except ValueError:  # nocoverage
            raise AssertionError("realm_id is not a number")

        # Check Charges in Stripe
        [charge] = iter(stripe.Charge.list(customer=stripe_customer.id))
        self.assertEqual(charge.amount, 8000 * self.seat_count)
        # TODO: fix Decimal
        self.assertEqual(
            charge.description, f"Upgrade to Zulip Cloud Standard, $80.0 x {self.seat_count}"
        )
        self.assertEqual(charge.receipt_email, user.delivery_email)
        self.assertEqual(charge.statement_descriptor, "Zulip Cloud Standard")
        # Check Invoices in Stripe
        [invoice] = iter(stripe.Invoice.list(customer=stripe_customer.id))
        self.assertIsNotNone(invoice.status_transitions.finalized_at)
        invoice_params = {
            # auto_advance is False because the invoice has been paid
            "amount_due": 0,
            "amount_paid": 0,
            "auto_advance": False,
            "collection_method": "charge_automatically",
            "charge": None,
            "status": "paid",
            "total": 0,
        }
        for key, value in invoice_params.items():
            self.assertEqual(invoice.get(key), value)
        # Check Line Items on Stripe Invoice
        [item0, item1] = iter(invoice.lines)
        line_item_params = {
            "amount": 8000 * self.seat_count,
            "description": "Zulip Cloud Standard",
            "discountable": False,
            "period": {
                "end": datetime_to_timestamp(self.next_year),
                "start": datetime_to_timestamp(self.now),
            },
            # There's no unit_amount on Line Items, probably because it doesn't show up on the
            # user-facing invoice. We could pull the Invoice Item instead and test unit_amount there,
            # but testing the amount and quantity seems sufficient.
            "plan": None,
            "proration": False,
            "quantity": self.seat_count,
        }
        for key, value in line_item_params.items():
            self.assertEqual(item0.get(key), value)
        line_item_params = {
            "amount": -8000 * self.seat_count,
            "description": "Payment (Card ending in 4242)",
            "discountable": False,
            "plan": None,
            "proration": False,
            "quantity": 1,
        }
        for key, value in line_item_params.items():
            self.assertEqual(item1.get(key), value)

        # Check that we correctly populated Customer, CustomerPlan, and LicenseLedger in Zulip
        customer = Customer.objects.get(stripe_customer_id=stripe_customer.id, realm=user.realm)
        plan = CustomerPlan.objects.get(
            customer=customer,
            automanage_licenses=True,
            price_per_license=8000,
            fixed_price=None,
            discount=None,
            billing_cycle_anchor=self.now,
            billing_schedule=CustomerPlan.BILLING_SCHEDULE_ANNUAL,
            invoiced_through=LicenseLedger.objects.first(),
            next_invoice_date=self.next_month,
            tier=CustomerPlan.TIER_CLOUD_STANDARD,
            status=CustomerPlan.ACTIVE,
        )
        LicenseLedger.objects.get(
            plan=plan,
            is_renewal=True,
            event_time=self.now,
            licenses=self.seat_count,
            licenses_at_next_renewal=self.seat_count,
        )
        # Check RealmAuditLog
        audit_log_entries = list(
            RealmAuditLog.objects.filter(acting_user=user)
            .values_list("event_type", "event_time")
            .order_by("id")
        )
        self.assertEqual(
            audit_log_entries[:3],
            [
                (
                    RealmAuditLog.STRIPE_CUSTOMER_CREATED,
                    timestamp_to_datetime(stripe_customer.created),
                ),
                (RealmAuditLog.STRIPE_CARD_CHANGED, self.now),
                (RealmAuditLog.CUSTOMER_PLAN_CREATED, self.now),
            ],
        )
        self.assertEqual(audit_log_entries[3][0], RealmAuditLog.REALM_PLAN_TYPE_CHANGED)
        first_audit_log_entry = (
            RealmAuditLog.objects.filter(event_type=RealmAuditLog.CUSTOMER_PLAN_CREATED)
            .values_list("extra_data", flat=True)
            .first()
        )
        assert first_audit_log_entry is not None
        self.assertTrue(first_audit_log_entry["automanage_licenses"])
        # Check that we correctly updated Realm
        realm = get_realm("zulip")
        self.assertEqual(realm.plan_type, Realm.PLAN_TYPE_STANDARD)
        self.assertEqual(realm.max_invites, Realm.INVITES_STANDARD_REALM_DAILY_MAX)
        # Check that we can no longer access /upgrade
        response = self.client_get("/upgrade/")
        self.assertEqual(response.status_code, 302)
        self.assertEqual("http://zulip.testserver/billing", response["Location"])

        # Check /billing/ has the correct information
        with time_machine.travel(self.now, tick=False):
            response = self.client_get("/billing/")
        self.assert_not_in_success_response(["Pay annually"], response)
        for substring in [
            "Zulip Cloud Standard",
            str(self.seat_count),
            "Number of licenses",
            f"{ self.seat_count } (managed automatically)",
            "Your plan will automatically renew on",
            "January 2, 2013",
            f"${80 * self.seat_count}.00",
            "Visa ending in 4242",
            "Update card",
        ]:
            self.assert_in_response(substring, response)

        self.assert_not_in_success_response(
            [
                "Number of licenses for current billing period",
                "Your next invoice is due on",
            ],
            response,
        )

    @mock_stripe(tested_timestamp_fields=["created"])
    def test_card_attached_to_customer_but_payment_fails(self, *mocks: Mock) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)
        self.add_card_to_customer_for_upgrade(charge_succeeds=False)
        with self.assertLogs("corporate.stripe", "WARNING"):
            response = self.upgrade()
        self.assert_json_error_contains(response, "Your card was declined.")

        # Customer added a card which always requires authentication, we cannot
        # use these cards for automatic payments.
        # TODO: Add a test case for it here.

    @mock_stripe(tested_timestamp_fields=["created"])
    def test_upgrade_by_invoice(self, *mocks: Mock) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)
        # Click "Make payment" in Stripe Checkout
        with time_machine.travel(self.now, tick=False):
            self.upgrade(invoice=True)
        # Check that we correctly created a Customer in Stripe
        stripe_customer = stripe_get_customer(
            assert_is_not_none(Customer.objects.get(realm=user.realm).stripe_customer_id)
        )
        self.assertFalse(stripe_customer_has_credit_card_as_default_payment_method(stripe_customer))
        # It can take a second for Stripe to attach the source to the customer, and in
        # particular it may not be attached at the time stripe_get_customer is called above,
        # causing test flakes.
        # So commenting the next line out, but leaving it here so future readers know what
        # is supposed to happen here
        # self.assertEqual(stripe_customer.default_source.type, 'ach_credit_transfer')

        # Check Charges in Stripe
        self.assertFalse(stripe.Charge.list(customer=stripe_customer.id))
        # Check Invoices in Stripe
        [invoice] = iter(stripe.Invoice.list(customer=stripe_customer.id))
        self.assertIsNotNone(invoice.due_date)
        self.assertIsNotNone(invoice.status_transitions.finalized_at)
        invoice_params = {
            "amount_due": 8000 * 123,
            "amount_paid": 0,
            "attempt_count": 0,
            "auto_advance": True,
            "collection_method": "send_invoice",
            "statement_descriptor": "Zulip Cloud Standard",
            "status": "open",
            "total": 8000 * 123,
        }
        for key, value in invoice_params.items():
            self.assertEqual(invoice.get(key), value)
        # Check Line Items on Stripe Invoice
        [item] = iter(invoice.lines)
        line_item_params = {
            "amount": 8000 * 123,
            "description": "Zulip Cloud Standard",
            "discountable": False,
            "period": {
                "end": datetime_to_timestamp(self.next_year),
                "start": datetime_to_timestamp(self.now),
            },
            "plan": None,
            "proration": False,
            "quantity": 123,
        }
        for key, value in line_item_params.items():
            self.assertEqual(item.get(key), value)

        # Check that we correctly populated Customer, CustomerPlan and LicenseLedger in Zulip
        customer = Customer.objects.get(stripe_customer_id=stripe_customer.id, realm=user.realm)
        plan = CustomerPlan.objects.get(
            customer=customer,
            automanage_licenses=False,
            charge_automatically=False,
            price_per_license=8000,
            fixed_price=None,
            discount=None,
            billing_cycle_anchor=self.now,
            billing_schedule=CustomerPlan.BILLING_SCHEDULE_ANNUAL,
            invoiced_through=LicenseLedger.objects.first(),
            next_invoice_date=self.next_year,
            tier=CustomerPlan.TIER_CLOUD_STANDARD,
            status=CustomerPlan.ACTIVE,
        )
        LicenseLedger.objects.get(
            plan=plan,
            is_renewal=True,
            event_time=self.now,
            licenses=123,
            licenses_at_next_renewal=123,
        )
        # Check RealmAuditLog
        audit_log_entries = list(
            RealmAuditLog.objects.filter(acting_user=user)
            .values_list("event_type", "event_time")
            .order_by("id")
        )
        self.assertEqual(
            audit_log_entries[:2],
            [
                (
                    RealmAuditLog.STRIPE_CUSTOMER_CREATED,
                    timestamp_to_datetime(stripe_customer.created),
                ),
                (RealmAuditLog.CUSTOMER_PLAN_CREATED, self.now),
            ],
        )
        self.assertEqual(audit_log_entries[2][0], RealmAuditLog.REALM_PLAN_TYPE_CHANGED)
        first_audit_log_entry = (
            RealmAuditLog.objects.filter(event_type=RealmAuditLog.CUSTOMER_PLAN_CREATED)
            .values_list("extra_data", flat=True)
            .first()
        )
        assert first_audit_log_entry is not None
        self.assertFalse(first_audit_log_entry["automanage_licenses"])
        # Check that we correctly updated Realm
        realm = get_realm("zulip")
        self.assertEqual(realm.plan_type, Realm.PLAN_TYPE_STANDARD)
        self.assertEqual(realm.max_invites, Realm.INVITES_STANDARD_REALM_DAILY_MAX)
        # Check that we can no longer access /upgrade
        response = self.client_get("/upgrade/")
        self.assertEqual(response.status_code, 302)
        self.assertEqual("http://zulip.testserver/billing", response["Location"])

        # Check /billing/ has the correct information
        with time_machine.travel(self.now, tick=False):
            response = self.client_get("/billing/")
        self.assert_not_in_success_response(["Pay annually", "Update card"], response)
        for substring in [
            "Zulip Cloud Standard",
            str(123),
            "Number of licenses for current billing period",
            f"licenses ({self.seat_count} in use)",
            "Your next invoice is due on",
            "January 2, 2013",
            "$9,840.00",  # 9840 = 80 * 123
        ]:
            self.assert_in_response(substring, response)

    @mock_stripe(tested_timestamp_fields=["created"])
    def test_free_trial_upgrade_by_card(self, *mocks: Mock) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)

        with self.settings(CLOUD_FREE_TRIAL_DAYS=60):
            response = self.client_get("/upgrade/")
            free_trial_end_date = self.now + timedelta(days=60)

            self.assert_in_success_response(
                ["Your card will not be charged", "free trial", "60-day"], response
            )
            self.assertNotEqual(user.realm.plan_type, Realm.PLAN_TYPE_STANDARD)
            self.assertFalse(Customer.objects.filter(realm=user.realm).exists())

            # Require free trial users to add a credit card.
            with time_machine.travel(self.now, tick=False):
                with self.assertLogs("corporate.stripe", "WARNING"):
                    response = self.upgrade()
            self.assert_json_error(
                response, "Please add a credit card before starting your free trial."
            )

            stripe_customer = self.add_card_and_upgrade(user)

            self.assertEqual(PaymentIntent.objects.count(), 0)
            self.assertEqual(stripe_customer.description, "zulip (Zulip Dev)")
            self.assertEqual(stripe_customer.discount, None)
            self.assertEqual(stripe_customer.email, user.delivery_email)
            assert stripe_customer.metadata is not None
            metadata_dict = dict(stripe_customer.metadata)
            self.assertEqual(metadata_dict["realm_str"], "zulip")
            try:
                int(metadata_dict["realm_id"])
            except ValueError:  # nocoverage
                raise AssertionError("realm_id is not a number")

            self.assertFalse(stripe.Charge.list(customer=stripe_customer.id))

            self.assertFalse(stripe.Invoice.list(customer=stripe_customer.id))

            customer = Customer.objects.get(stripe_customer_id=stripe_customer.id, realm=user.realm)
            plan = CustomerPlan.objects.get(
                customer=customer,
                automanage_licenses=True,
                price_per_license=8000,
                fixed_price=None,
                discount=None,
                billing_cycle_anchor=self.now,
                billing_schedule=CustomerPlan.BILLING_SCHEDULE_ANNUAL,
                invoiced_through=LicenseLedger.objects.first(),
                next_invoice_date=free_trial_end_date,
                tier=CustomerPlan.TIER_CLOUD_STANDARD,
                status=CustomerPlan.FREE_TRIAL,
                # For payment through card.
                charge_automatically=True,
            )
            LicenseLedger.objects.get(
                plan=plan,
                is_renewal=True,
                event_time=self.now,
                licenses=self.seat_count,
                licenses_at_next_renewal=self.seat_count,
            )
            audit_log_entries = list(
                RealmAuditLog.objects.filter(acting_user=user)
                .values_list("event_type", "event_time")
                .order_by("id")
            )
            self.assertEqual(
                audit_log_entries[:3],
                [
                    (
                        RealmAuditLog.STRIPE_CUSTOMER_CREATED,
                        timestamp_to_datetime(stripe_customer.created),
                    ),
                    (
                        RealmAuditLog.STRIPE_CARD_CHANGED,
                        self.now,
                    ),
                    (RealmAuditLog.CUSTOMER_PLAN_CREATED, self.now),
                ],
            )
            self.assertEqual(audit_log_entries[3][0], RealmAuditLog.REALM_PLAN_TYPE_CHANGED)
            first_audit_log_entry = (
                RealmAuditLog.objects.filter(event_type=RealmAuditLog.CUSTOMER_PLAN_CREATED)
                .values_list("extra_data", flat=True)
                .first()
            )
            assert first_audit_log_entry is not None
            self.assertTrue(first_audit_log_entry["automanage_licenses"])

            realm = get_realm("zulip")
            self.assertEqual(realm.plan_type, Realm.PLAN_TYPE_STANDARD)
            self.assertEqual(realm.max_invites, Realm.INVITES_STANDARD_REALM_DAILY_MAX)

            with time_machine.travel(self.now, tick=False):
                response = self.client_get("/billing/")
            self.assert_not_in_success_response(["Pay annually"], response)
            for substring in [
                "Zulip Cloud Standard <i>(free trial)</i>",
                str(self.seat_count),
                "Number of licenses",
                f"{self.seat_count} (managed automatically)",
                "Your plan will automatically renew on",
                "March 2, 2012",
                f"${80 * self.seat_count}.00",
                "Visa ending in 4242",
                "Update card",
            ]:
                self.assert_in_response(substring, response)
            self.assert_not_in_success_response(["Go to your Zulip organization"], response)

            billing_session = RealmBillingSession(user=user, realm=realm)
            with patch("corporate.lib.stripe.get_latest_seat_count", return_value=12):
                billing_session.update_license_ledger_if_needed(self.now)
            self.assertEqual(
                LicenseLedger.objects.order_by("-id")
                .values_list("licenses", "licenses_at_next_renewal")
                .first(),
                (12, 12),
            )

            with patch("corporate.lib.stripe.get_latest_seat_count", return_value=15):
                billing_session.update_license_ledger_if_needed(self.next_month)
            self.assertEqual(
                LicenseLedger.objects.order_by("-id")
                .values_list("licenses", "licenses_at_next_renewal")
                .first(),
                (15, 15),
            )

            invoice_plans_as_needed(self.next_month)
            self.assertFalse(stripe.Invoice.list(customer=stripe_customer.id))
            customer_plan = CustomerPlan.objects.get(customer=customer)
            self.assertEqual(customer_plan.status, CustomerPlan.FREE_TRIAL)
            self.assertEqual(customer_plan.next_invoice_date, free_trial_end_date)

            invoice_plans_as_needed(free_trial_end_date)
            customer_plan.refresh_from_db()
            realm.refresh_from_db()
            self.assertEqual(customer_plan.status, CustomerPlan.ACTIVE)
            self.assertEqual(customer_plan.next_invoice_date, add_months(free_trial_end_date, 1))
            self.assertEqual(realm.plan_type, Realm.PLAN_TYPE_STANDARD)
            [invoice] = iter(stripe.Invoice.list(customer=stripe_customer.id))
            invoice_params = {
                "amount_due": 15 * 80 * 100,
                "amount_paid": 0,
                "amount_remaining": 15 * 80 * 100,
                "auto_advance": True,
                "collection_method": "charge_automatically",
                "customer_email": self.example_email("hamlet"),
                "discount": None,
                "paid": False,
                "status": "open",
                "total": 15 * 80 * 100,
            }
            for key, value in invoice_params.items():
                self.assertEqual(invoice.get(key), value)
            [invoice_item] = iter(invoice.lines)
            invoice_item_params = {
                "amount": 15 * 80 * 100,
                "description": "Zulip Cloud Standard - renewal",
                "plan": None,
                "quantity": 15,
                "subscription": None,
                "discountable": False,
                "period": {
                    "start": datetime_to_timestamp(free_trial_end_date),
                    "end": datetime_to_timestamp(add_months(free_trial_end_date, 12)),
                },
            }
            for key, value in invoice_item_params.items():
                self.assertEqual(invoice_item[key], value)

            invoice_plans_as_needed(add_months(free_trial_end_date, 1))
            [invoice] = iter(stripe.Invoice.list(customer=stripe_customer.id))

            with patch("corporate.lib.stripe.get_latest_seat_count", return_value=19):
                billing_session.update_license_ledger_if_needed(add_months(free_trial_end_date, 10))
            self.assertEqual(
                LicenseLedger.objects.order_by("-id")
                .values_list("licenses", "licenses_at_next_renewal")
                .first(),
                (19, 19),
            )
            invoice_plans_as_needed(add_months(free_trial_end_date, 10))
            [invoice0, invoice1] = iter(stripe.Invoice.list(customer=stripe_customer.id))
            invoice_params = {
                "amount_due": 5172,
                "auto_advance": True,
                "collection_method": "charge_automatically",
                "customer_email": "hamlet@zulip.com",
            }
            [invoice_item] = iter(invoice0.lines)
            invoice_item_params = {
                "amount": 5172,
                "description": "Additional license (Jan 2, 2013 - Mar 2, 2013)",
                "discountable": False,
                "quantity": 4,
                "period": {
                    "start": datetime_to_timestamp(add_months(free_trial_end_date, 10)),
                    "end": datetime_to_timestamp(add_months(free_trial_end_date, 12)),
                },
            }

            invoice_plans_as_needed(add_months(free_trial_end_date, 12))
            [invoice0, invoice1, invoice2] = iter(stripe.Invoice.list(customer=stripe_customer.id))

        # Check /billing/ has correct information for fixed price customers.
        plan.fixed_price = 127
        plan.price_per_license = None
        plan.save(update_fields=["fixed_price", "price_per_license"])
        with time_machine.travel(self.now, tick=False):
            response = self.client_get("/billing/")
        self.assert_in_success_response(["$1.27"], response)
        # Don't show price breakdown
        self.assert_not_in_success_response(["{self.seat_count} x"], response)

    @mock_stripe(tested_timestamp_fields=["created"])
    def test_free_trial_upgrade_by_invoice(self, *mocks: Mock) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)

        free_trial_end_date = self.now + timedelta(days=60)
        with self.settings(CLOUD_FREE_TRIAL_DAYS=60):
            response = self.client_get("/upgrade/")

            self.assert_in_success_response(
                ["Your card will not be charged", "free trial", "60-day"], response
            )
            self.assertNotEqual(user.realm.plan_type, Realm.PLAN_TYPE_STANDARD)
            self.assertFalse(Customer.objects.filter(realm=user.realm).exists())

            with time_machine.travel(self.now, tick=False):
                self.upgrade(invoice=True)

            stripe_customer = stripe_get_customer(
                assert_is_not_none(Customer.objects.get(realm=user.realm).stripe_customer_id)
            )
            self.assertEqual(stripe_customer.discount, None)
            self.assertEqual(stripe_customer.email, user.delivery_email)
            assert stripe_customer.metadata is not None
            metadata_dict = dict(stripe_customer.metadata)
            self.assertEqual(metadata_dict["realm_str"], "zulip")
            try:
                int(metadata_dict["realm_id"])
            except ValueError:  # nocoverage
                raise AssertionError("realm_id is not a number")

            self.assertFalse(stripe.Invoice.list(customer=stripe_customer.id))

            customer = Customer.objects.get(stripe_customer_id=stripe_customer.id, realm=user.realm)
            plan = CustomerPlan.objects.get(
                customer=customer,
                automanage_licenses=False,
                price_per_license=8000,
                fixed_price=None,
                discount=None,
                billing_cycle_anchor=self.now,
                billing_schedule=CustomerPlan.BILLING_SCHEDULE_ANNUAL,
                invoiced_through=LicenseLedger.objects.first(),
                next_invoice_date=free_trial_end_date,
                tier=CustomerPlan.TIER_CLOUD_STANDARD,
                status=CustomerPlan.FREE_TRIAL,
                # For invoice billing.
                charge_automatically=False,
            )

            LicenseLedger.objects.get(
                plan=plan,
                is_renewal=True,
                event_time=self.now,
                licenses=123,
                licenses_at_next_renewal=123,
            )
            audit_log_entries = list(
                RealmAuditLog.objects.filter(acting_user=user)
                .values_list("event_type", "event_time")
                .order_by("id")
            )
            self.assertEqual(
                audit_log_entries[:2],
                [
                    (
                        RealmAuditLog.STRIPE_CUSTOMER_CREATED,
                        timestamp_to_datetime(stripe_customer.created),
                    ),
                    (RealmAuditLog.CUSTOMER_PLAN_CREATED, self.now),
                ],
            )
            self.assertEqual(audit_log_entries[2][0], RealmAuditLog.REALM_PLAN_TYPE_CHANGED)
            first_audit_log_entry = (
                RealmAuditLog.objects.filter(event_type=RealmAuditLog.CUSTOMER_PLAN_CREATED)
                .values_list("extra_data", flat=True)
                .first()
            )
            assert first_audit_log_entry is not None
            self.assertFalse(first_audit_log_entry["automanage_licenses"])

            realm = get_realm("zulip")
            self.assertEqual(realm.plan_type, Realm.PLAN_TYPE_STANDARD)
            self.assertEqual(realm.max_invites, Realm.INVITES_STANDARD_REALM_DAILY_MAX)

            with time_machine.travel(self.now, tick=False):
                response = self.client_get("/billing/")
            self.assert_not_in_success_response(["Pay annually"], response)
            for substring in [
                "Zulip Cloud Standard <i>(free trial)</i>",
                str(self.seat_count),
                "Number of licenses for next billing period",
                f"{self.seat_count} in use",
                "Your next invoice is due on",
                "March 2, 2012",
                f"{80 * 123:,.2f}",
                "Billed by invoice",
            ]:
                self.assert_in_response(substring, response)

            with patch("corporate.lib.stripe.BillingSession.invoice_plan") as mocked:
                invoice_plans_as_needed(self.next_month)
            mocked.assert_not_called()
            mocked.reset_mock()
            customer_plan = CustomerPlan.objects.get(customer=customer)
            self.assertEqual(customer_plan.status, CustomerPlan.FREE_TRIAL)
            self.assertEqual(customer_plan.next_invoice_date, free_trial_end_date)

            invoice_plans_as_needed(free_trial_end_date)
            customer_plan.refresh_from_db()
            realm.refresh_from_db()
            self.assertEqual(customer_plan.status, CustomerPlan.ACTIVE)
            self.assertEqual(customer_plan.next_invoice_date, add_months(free_trial_end_date, 12))
            self.assertEqual(realm.plan_type, Realm.PLAN_TYPE_STANDARD)
            [invoice] = iter(stripe.Invoice.list(customer=stripe_customer.id))
            invoice_params = {
                "amount_due": 123 * 80 * 100,
                "amount_paid": 0,
                "amount_remaining": 123 * 80 * 100,
                "auto_advance": True,
                "collection_method": "send_invoice",
                "customer_email": self.example_email("hamlet"),
                "discount": None,
                "paid": False,
                "status": "open",
                "total": 123 * 80 * 100,
            }
            for key, value in invoice_params.items():
                self.assertEqual(invoice.get(key), value)
            [invoice_item] = iter(invoice.lines)
            invoice_item_params = {
                "amount": 123 * 80 * 100,
                "description": "Zulip Cloud Standard - renewal",
                "plan": None,
                "quantity": 123,
                "subscription": None,
                "discountable": False,
                "period": {
                    "start": datetime_to_timestamp(free_trial_end_date),
                    "end": datetime_to_timestamp(add_months(free_trial_end_date, 12)),
                },
            }
            for key, value in invoice_item_params.items():
                self.assertEqual(invoice_item[key], value)

            invoice_plans_as_needed(add_months(free_trial_end_date, 1))
            [invoice] = iter(stripe.Invoice.list(customer=stripe_customer.id))

            invoice_plans_as_needed(add_months(free_trial_end_date, 10))
            [invoice] = iter(stripe.Invoice.list(customer=stripe_customer.id))

            invoice_plans_as_needed(add_months(free_trial_end_date, 12))
            [invoice0, invoice1] = iter(stripe.Invoice.list(customer=stripe_customer.id))

    @mock_stripe(tested_timestamp_fields=["created"])
    def test_upgrade_by_card_with_outdated_seat_count(self, *mocks: Mock) -> None:
        hamlet = self.example_user("hamlet")
        self.login_user(hamlet)
        new_seat_count = 23
        initial_upgrade_request = InitialUpgradeRequest(
            manual_license_management=False,
            tier=CustomerPlan.TIER_CLOUD_STANDARD,
        )
        billing_session = RealmBillingSession(hamlet)
        _, context_when_upgrade_page_is_rendered = billing_session.get_initial_upgrade_context(
            initial_upgrade_request
        )
        # Change the seat count while the user is going through the upgrade flow
        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=new_seat_count):
            with patch(
                "corporate.lib.stripe.RealmBillingSession.get_initial_upgrade_context",
                return_value=(_, context_when_upgrade_page_is_rendered),
            ):
                self.add_card_and_upgrade(hamlet)

        customer = Customer.objects.first()
        assert customer is not None
        stripe_customer_id: str = assert_is_not_none(customer.stripe_customer_id)
        # Check that the Charge used the old quantity, not new_seat_count
        [charge] = iter(stripe.Charge.list(customer=stripe_customer_id))
        self.assertEqual(8000 * self.seat_count, charge.amount)
        # Check that the invoice has a credit for the old amount and a charge for the new one
        [stripe_invoice] = iter(stripe.Invoice.list(customer=stripe_customer_id))
        self.assertEqual(
            [8000 * new_seat_count, -8000 * self.seat_count],
            [item.amount for item in stripe_invoice.lines],
        )
        # Check LicenseLedger has the new amount
        ledger_entry = LicenseLedger.objects.first()
        assert ledger_entry is not None
        self.assertEqual(ledger_entry.licenses, new_seat_count)
        self.assertEqual(ledger_entry.licenses_at_next_renewal, new_seat_count)

    def test_upgrade_with_tampered_seat_count(self) -> None:
        hamlet = self.example_user("hamlet")
        self.login_user(hamlet)
        with self.assertLogs("corporate.stripe", "WARNING"):
            response = self.upgrade(talk_to_stripe=False, salt="badsalt")
        self.assert_json_error_contains(response, "Something went wrong. Please contact")
        self.assertEqual(orjson.loads(response.content)["error_description"], "tampered seat count")

    @mock_stripe()
    def test_upgrade_race_condition_during_card_upgrade(self, *mocks: Mock) -> None:
        hamlet = self.example_user("hamlet")
        othello = self.example_user("othello")

        self.login_user(hamlet)
        hamlet_upgrade_page_response = self.client_get("/upgrade/")
        self.add_card_to_customer_for_upgrade()
        self.client_post(
            "/json/billing/upgrade",
            {
                "billing_modality": "charge_automatically",
                "schedule": "annual",
                "signed_seat_count": self.get_signed_seat_count_from_response(
                    hamlet_upgrade_page_response
                ),
                "salt": self.get_salt_from_response(hamlet_upgrade_page_response),
                "license_management": "automatic",
            },
        )
        # Hamlet already paid to upgrade the org but we haven't received a success event for it yet.
        [hamlet_payment_success_event] = iter(
            stripe.Event.list(type="payment_intent.succeeded", limit=1)
        )
        [hamlet_payment_intent] = iter(stripe.PaymentIntent.list(limit=1))

        self.login_user(othello)
        # Othello completed the upgrade while we were waiting on success payment event for Hamlet.
        self.upgrade()

        with self.assertLogs("corporate.stripe", "WARNING"):
            self.send_stripe_webhook_event(hamlet_payment_success_event)

        self.assert_details_of_valid_payment_intent_from_event_status_endpoint(
            hamlet_payment_intent.id,
            {
                "status": "succeeded",
                "event_handler": {
                    "status": "failed",
                    "error": {
                        "message": "The organization is already subscribed to a plan. Please reload the billing page.",
                        "description": "subscribing with existing subscription",
                    },
                },
            },
        )
        charged_amount = self.seat_count * 8000
        customer = get_customer_by_realm(get_realm("zulip"))
        assert customer is not None
        assert customer.stripe_customer_id is not None
        [invoice, _] = iter(stripe.Invoice.list(customer=customer.stripe_customer_id))
        self.assertEqual(invoice.total, -1 * charged_amount)
        stripe_customer = stripe.Customer.retrieve(customer.stripe_customer_id)
        self.assertEqual(stripe_customer.balance, -1 * charged_amount)

    def test_upgrade_race_condition_during_invoice_upgrade(self) -> None:
        hamlet = self.example_user("hamlet")
        self.login_user(hamlet)
        self.local_upgrade(self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False)
        with self.assertLogs("corporate.stripe", "WARNING") as m:
            with self.assertRaises(BillingError) as context:
                self.local_upgrade(
                    self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
                )
        self.assertEqual(
            "subscribing with existing subscription", context.exception.error_description
        )
        self.assertEqual(
            m.output[0],
            "WARNING:corporate.stripe:Upgrade of <Realm: zulip 2> (with stripe_customer_id: cus_123) failed because of existing active plan.",
        )
        self.assert_length(m.output, 1)

    @mock_stripe(tested_timestamp_fields=["created"])
    def test_check_upgrade_parameters(self, *mocks: Mock) -> None:
        # Tests all the error paths except 'not enough licenses'
        def check_error(
            error_message: str,
            error_description: str,
            upgrade_params: Mapping[str, Any],
            del_args: Sequence[str] = [],
        ) -> None:
            self.add_card_to_customer_for_upgrade()
            if error_description:
                with self.assertLogs("corporate.stripe", "WARNING"):
                    response = self.upgrade(
                        talk_to_stripe=False, del_args=del_args, **upgrade_params
                    )
                    self.assertEqual(
                        orjson.loads(response.content)["error_description"], error_description
                    )
            else:
                response = self.upgrade(talk_to_stripe=False, del_args=del_args, **upgrade_params)
            self.assert_json_error_contains(response, error_message)

        hamlet = self.example_user("hamlet")
        self.login_user(hamlet)
        check_error("Invalid billing_modality", "", {"billing_modality": "invalid"})
        check_error("Invalid schedule", "", {"schedule": "invalid"})
        check_error("Invalid license_management", "", {"license_management": "invalid"})

        check_error(
            "You must purchase licenses for all active users in your organization (minimum 30).",
            "not enough licenses",
            {"billing_modality": "send_invoice", "licenses": -1},
        )
        check_error(
            "You must purchase licenses for all active users in your organization (minimum 30).",
            "not enough licenses",
            {"billing_modality": "send_invoice"},
        )
        check_error(
            "You must purchase licenses for all active users in your organization (minimum 30).",
            "not enough licenses",
            {"billing_modality": "send_invoice", "licenses": 25},
        )
        check_error(
            "Invoices with more than 1000 licenses can't be processed from this page",
            "too many licenses",
            {"billing_modality": "send_invoice", "licenses": 10000},
        )

        check_error(
            "You must purchase licenses for all active users in your organization (minimum 6).",
            "not enough licenses",
            {"billing_modality": "charge_automatically", "license_management": "manual"},
        )

        check_error(
            "You must purchase licenses for all active users in your organization (minimum 6).",
            "not enough licenses",
            {
                "billing_modality": "charge_automatically",
                "license_management": "manual",
                "licenses": 3,
            },
        )

    @mock_stripe(tested_timestamp_fields=["created"])
    def test_upgrade_license_counts(self, *mocks: Mock) -> None:
        hamlet = self.example_user("hamlet")
        self.login_user(hamlet)
        self.add_card_to_customer_for_upgrade()

        def check_min_licenses_error(
            invoice: bool,
            licenses: Optional[int],
            min_licenses_in_response: int,
            upgrade_params: Mapping[str, Any] = {},
        ) -> None:
            upgrade_params = dict(upgrade_params)
            if licenses is None:
                del_args = ["licenses"]
            else:
                del_args = []
                upgrade_params["licenses"] = licenses
            with self.assertLogs("corporate.stripe", "WARNING"):
                response = self.upgrade(
                    invoice=invoice, talk_to_stripe=False, del_args=del_args, **upgrade_params
                )
            self.assert_json_error_contains(response, f"minimum {min_licenses_in_response}")
            self.assertEqual(
                orjson.loads(response.content)["error_description"], "not enough licenses"
            )

        def check_max_licenses_error(licenses: int) -> None:
            with self.assertLogs("corporate.stripe", "WARNING"):
                response = self.upgrade(invoice=True, talk_to_stripe=False, licenses=licenses)
            self.assert_json_error_contains(
                response, f"with more than {MAX_INVOICED_LICENSES} licenses"
            )
            self.assertEqual(
                orjson.loads(response.content)["error_description"], "too many licenses"
            )

        def check_success(
            invoice: bool, licenses: Optional[int], upgrade_params: Mapping[str, Any] = {}
        ) -> None:
            upgrade_params = dict(upgrade_params)
            if licenses is None:
                del_args = ["licenses"]
            else:
                del_args = []
                upgrade_params["licenses"] = licenses
            with patch("corporate.lib.stripe.BillingSession.process_initial_upgrade"):
                with patch(
                    "corporate.lib.stripe.BillingSession.create_stripe_payment_intent",
                    return_value="fake_payment_intent_id",
                ):
                    response = self.upgrade(
                        invoice=invoice, talk_to_stripe=False, del_args=del_args, **upgrade_params
                    )
            self.assert_json_success(response)

        # Autopay with licenses < seat count
        check_min_licenses_error(
            False, self.seat_count - 1, self.seat_count, {"license_management": "manual"}
        )
        # Autopay with not setting licenses
        check_min_licenses_error(False, None, self.seat_count, {"license_management": "manual"})
        # Invoice with licenses < MIN_INVOICED_LICENSES
        check_min_licenses_error(True, MIN_INVOICED_LICENSES - 1, MIN_INVOICED_LICENSES)
        # Invoice with licenses < seat count
        with patch("corporate.lib.stripe.MIN_INVOICED_LICENSES", 3):
            check_min_licenses_error(True, 4, self.seat_count)
        # Invoice with not setting licenses
        check_min_licenses_error(True, None, MIN_INVOICED_LICENSES)
        # Invoice exceeding max licenses
        check_max_licenses_error(MAX_INVOICED_LICENSES + 1)
        with patch(
            "corporate.lib.stripe.get_latest_seat_count", return_value=MAX_INVOICED_LICENSES + 5
        ):
            check_max_licenses_error(MAX_INVOICED_LICENSES + 5)

        # Autopay with automatic license_management
        check_success(False, None)
        # Autopay with automatic license_management, should just ignore the licenses entry
        check_success(False, self.seat_count)
        # Autopay
        check_success(False, self.seat_count, {"license_management": "manual"})
        # Autopay has no limit on max licenses
        check_success(False, MAX_INVOICED_LICENSES + 1, {"license_management": "manual"})
        # Invoice
        check_success(True, self.seat_count + MIN_INVOICED_LICENSES)
        # Invoice
        check_success(True, MAX_INVOICED_LICENSES)

        # By default, an organization on a "Pay by card" plan with Manual license
        # management cannot purchase less licenses than the current seat count.
        # If exempt_from_license_number_check is enabled, they should be able to though.
        customer = Customer.objects.get_or_create(realm=hamlet.realm)[0]
        customer.exempt_from_license_number_check = True
        customer.save()
        check_success(False, self.seat_count - 1, {"license_management": "manual"})

    @mock_stripe(tested_timestamp_fields=["created"])
    def test_upgrade_with_uncaught_exception(self, *mock_args: Any) -> None:
        hamlet = self.example_user("hamlet")
        self.login_user(hamlet)
        self.add_card_to_customer_for_upgrade()
        with patch(
            "corporate.lib.stripe.BillingSession.create_stripe_payment_intent",
            side_effect=Exception,
        ), self.assertLogs("corporate.stripe", "WARNING") as m:
            response = self.upgrade(talk_to_stripe=False)
            self.assertIn("ERROR:corporate.stripe:Uncaught exception in billing", m.output[0])
            self.assertIn(m.records[0].stack_info, m.output[0])
        self.assert_json_error_contains(
            response, "Something went wrong. Please contact desdemona+admin@zulip.com."
        )
        self.assertEqual(
            orjson.loads(response.content)["error_description"], "uncaught exception during upgrade"
        )

    @mock_stripe(tested_timestamp_fields=["created"])
    def test_payment_intent_succeeded_event_with_uncaught_exception(self, *mock_args: Any) -> None:
        hamlet = self.example_user("hamlet")
        self.login_user(hamlet)
        self.add_card_to_customer_for_upgrade()

        with patch(
            "corporate.lib.stripe.BillingSession.process_initial_upgrade", side_effect=Exception
        ), self.assertLogs("corporate.stripe", "WARNING"):
            response = self.upgrade()

        response_dict = self.assert_json_success(response)

        self.assert_details_of_valid_payment_intent_from_event_status_endpoint(
            response_dict["stripe_payment_intent_id"],
            {
                "status": "succeeded",
                "event_handler": {
                    "status": "failed",
                    "error": {
                        "message": "Something went wrong. Please contact desdemona+admin@zulip.com.",
                        "description": "uncaught exception in payment_intent.succeeded event handler",
                    },
                },
            },
        )

    def test_request_sponsorship_form_with_invalid_url(self) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)
        data = {
            "organization_type": Realm.ORG_TYPES["opensource"]["id"],
            "website": "invalid-url",
            "description": "Infinispan is a distributed in-memory key/value data store with optional schema.",
            "expected_total_users": "10 users",
            "paid_users_count": "1 user",
            "paid_users_description": "We have 1 paid user.",
        }

        response = self.client_post("/json/billing/sponsorship", data)

        self.assert_json_error(response, "Enter a valid URL.")

    def test_request_sponsorship_form_with_blank_url(self) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)
        data = {
            "organization_type": Realm.ORG_TYPES["opensource"]["id"],
            "website": "",
            "description": "Infinispan is a distributed in-memory key/value data store with optional schema.",
            "expected_total_users": "10 users",
            "paid_users_count": "1 user",
            "paid_users_description": "We have 1 paid user.",
        }

        response = self.client_post("/json/billing/sponsorship", data)

        self.assert_json_success(response)

    @mock_stripe()
    def test_sponsorship_access_for_realms_on_paid_plan(self, *mocks: Mock) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)
        self.add_card_and_upgrade(user)
        response = self.client_get("/sponsorship/")
        self.assert_in_success_response(
            [
                "How many paid staff does your organization have?",
            ],
            response,
        )

    def test_support_request(self) -> None:
        user = self.example_user("hamlet")
        self.assertIsNone(get_customer_by_realm(user.realm))

        self.login_user(user)

        result = self.client_get("/support/")
        self.assertEqual(result.status_code, 200)
        self.assert_in_success_response(["Contact support"], result)

        data = {
            "request_subject": "Not getting messages.",
            "request_message": "Running into this weird issue.",
        }
        result = self.client_post("/support/", data)
        self.assert_in_success_response(["Thanks for contacting us!"], result)

        from django.core.mail import outbox

        self.assert_length(outbox, 1)

        for message in outbox:
            self.assert_length(message.to, 1)
            self.assertEqual(message.to[0], "desdemona+admin@zulip.com")
            self.assertEqual(message.subject, "Support request for zulip")
            self.assertEqual(message.reply_to, ["hamlet@zulip.com"])
            self.assertEqual(self.email_envelope_from(message), settings.NOREPLY_EMAIL_ADDRESS)
            self.assertIn("Zulip support request <noreply-", self.email_display_from(message))
            self.assertIn("Requested by: King Hamlet (Member)", message.body)
            self.assertIn(
                "Support URL: http://zulip.testserver/activity/support?q=zulip", message.body
            )
            self.assertIn("Subject: Not getting messages.", message.body)
            self.assertIn("Message:\nRunning into this weird issue", message.body)

    def test_request_sponsorship(self) -> None:
        user = self.example_user("hamlet")
        self.assertIsNone(get_customer_by_realm(user.realm))

        self.login_user(user)

        data = {
            "organization_type": Realm.ORG_TYPES["opensource"]["id"],
            "website": "https://infinispan.org/",
            "description": "Infinispan is a distributed in-memory key/value data store with optional schema.",
            "expected_total_users": "10 users",
            "paid_users_count": "1 user",
            "paid_users_description": "We have 1 paid user.",
        }
        response = self.client_post("/json/billing/sponsorship", data)
        self.assert_json_success(response)

        customer = get_customer_by_realm(user.realm)
        assert customer is not None
        sponsorship_request = ZulipSponsorshipRequest.objects.filter(
            customer=customer, requested_by=user
        ).first()
        assert sponsorship_request is not None
        self.assertEqual(sponsorship_request.org_website, data["website"])
        self.assertEqual(sponsorship_request.org_description, data["description"])
        self.assertEqual(
            sponsorship_request.org_type,
            Realm.ORG_TYPES["opensource"]["id"],
        )

        customer = get_customer_by_realm(user.realm)
        assert customer is not None
        self.assertEqual(customer.sponsorship_pending, True)
        from django.core.mail import outbox

        self.assert_length(outbox, 1)

        for message in outbox:
            self.assert_length(message.to, 1)
            self.assertEqual(message.to[0], "desdemona+admin@zulip.com")
            self.assertEqual(message.subject, "Sponsorship request (Open-source project) for zulip")
            self.assertEqual(message.reply_to, ["hamlet@zulip.com"])
            self.assertEqual(self.email_envelope_from(message), settings.NOREPLY_EMAIL_ADDRESS)
            self.assertIn("Zulip sponsorship request <noreply-", self.email_display_from(message))
            self.assertIn("Requested by: King Hamlet (Member)", message.body)
            self.assertIn(
                "Support URL: http://zulip.testserver/activity/support?q=zulip", message.body
            )
            self.assertIn("Website: https://infinispan.org", message.body)
            self.assertIn("Organization type: Open-source", message.body)
            self.assertIn("Description:\nInfinispan is a distributed in-memory", message.body)

        response = self.client_get("/upgrade/")
        self.assertEqual(response.status_code, 302)
        self.assertEqual(response["Location"], "http://zulip.testserver/sponsorship")

        response = self.client_get("/billing/")
        self.assertEqual(response.status_code, 302)
        self.assertEqual(response["Location"], "/sponsorship/")

        response = self.client_get("/sponsorship/")
        self.assert_in_success_response(
            [
                "This organization has requested sponsorship for a",
                '<a href="/plans/">Zulip Cloud Standard</a>',
                'plan.<br/><a href="mailto:support@zulip.com">Contact Zulip support</a> with any questions or updates.',
            ],
            response,
        )

        self.login_user(self.example_user("othello"))
        response = self.client_get("/billing/")
        self.assert_in_success_response(
            ["You must be an organization owner or a billing administrator to view this page."],
            response,
        )

        user.realm.plan_type = Realm.PLAN_TYPE_PLUS
        user.realm.save()
        response = self.client_get("/sponsorship/")
        self.assertEqual(response.status_code, 302)
        self.assertEqual(response["Location"], "/billing/")

        user.realm.plan_type = Realm.PLAN_TYPE_STANDARD_FREE
        user.realm.save()
        self.login_user(self.example_user("hamlet"))
        response = self.client_get("/sponsorship/")
        self.assert_in_success_response(
            [
                'Zulip is sponsoring a free <a href="/plans/">Zulip Cloud Standard</a> plan for this organization. 🎉'
            ],
            response,
        )

    def test_redirect_for_billing_page(self) -> None:
        user = self.example_user("iago")
        self.login_user(user)
        response = self.client_get("/billing/")
        not_admin_message = (
            "You must be an organization owner or a billing administrator to view this page."
        )
        self.assert_in_success_response([not_admin_message], response)

        user.realm.plan_type = Realm.PLAN_TYPE_STANDARD_FREE
        user.realm.save()
        response = self.client_get("/billing/")
        self.assert_in_success_response([not_admin_message], response)

        # Billing page redirects to sponsorship page for standard free admins.
        user = self.example_user("hamlet")
        self.login_user(user)
        response = self.client_get("/billing/")
        self.assertEqual(response.status_code, 302)
        self.assertEqual("/sponsorship/", response["Location"])

        user.realm.plan_type = Realm.PLAN_TYPE_LIMITED
        user.realm.save()
        customer = Customer.objects.create(realm=user.realm, stripe_customer_id="cus_123")
        response = self.client_get("/billing/")
        self.assertEqual(response.status_code, 302)
        self.assertEqual("/plans/", response["Location"])

        # Check redirects for sponsorship pending
        customer.sponsorship_pending = True
        customer.save()
        response = self.client_get("/billing/")
        self.assertEqual(response.status_code, 302)
        self.assertEqual("/sponsorship/", response["Location"])

        # Don't redirect to sponsorship for paid plans.
        user.realm.plan_type = Realm.PLAN_TYPE_STANDARD
        user.realm.save()
        response = self.client_get("/billing/")
        self.assertNotEqual("/sponsorship/", response["Location"])

        user.realm.plan_type = Realm.PLAN_TYPE_PLUS
        user.realm.save()
        response = self.client_get("/billing/")
        self.assertNotEqual("/sponsorship/", response["Location"])

    def test_upgrade_page_for_demo_organizations(self) -> None:
        user = self.example_user("hamlet")
        user.realm.demo_organization_scheduled_deletion_date = timezone_now() + timedelta(days=30)
        user.realm.save()
        self.login_user(user)

        response = self.client_get("/billing/", follow=True)
        self.assert_in_success_response(["cannot be directly upgraded"], response)

    def test_redirect_for_upgrade_page(self) -> None:
        user = self.example_user("iago")
        self.login_user(user)

        response = self.client_get("/upgrade/")
        self.assertEqual(response.status_code, 200)

        user.realm.plan_type = Realm.PLAN_TYPE_STANDARD_FREE
        user.realm.save()
        response = self.client_get("/upgrade/")
        self.assertEqual(response.status_code, 302)
        self.assertEqual(response["Location"], "http://zulip.testserver/sponsorship")

        # Avoid contacting stripe as we only want to check redirects here.
        with patch(
            "corporate.lib.stripe.customer_has_credit_card_as_default_payment_method",
            return_value=False,
        ):
            user.realm.plan_type = Realm.PLAN_TYPE_LIMITED
            user.realm.save()
            customer = Customer.objects.create(realm=user.realm, stripe_customer_id="cus_123")
            response = self.client_get("/upgrade/")
            self.assertEqual(response.status_code, 200)

            CustomerPlan.objects.create(
                customer=customer,
                billing_cycle_anchor=timezone_now(),
                billing_schedule=CustomerPlan.BILLING_SCHEDULE_ANNUAL,
                tier=CustomerPlan.TIER_CLOUD_STANDARD,
            )
            response = self.client_get("/upgrade/")
            self.assertEqual(response.status_code, 302)
            self.assertEqual(response["Location"], "http://zulip.testserver/billing")

            with self.settings(CLOUD_FREE_TRIAL_DAYS=30):
                response = self.client_get("/upgrade/")
                self.assertEqual(response.status_code, 302)
                self.assertEqual(response["Location"], "http://zulip.testserver/billing")

    def test_get_latest_seat_count(self) -> None:
        realm = get_realm("zulip")
        initial_count = get_latest_seat_count(realm)
        user1 = UserProfile.objects.create(
            realm=realm, email="user1@zulip.com", delivery_email="user1@zulip.com"
        )
        user2 = UserProfile.objects.create(
            realm=realm, email="user2@zulip.com", delivery_email="user2@zulip.com"
        )
        self.assertEqual(get_latest_seat_count(realm), initial_count + 2)

        # Test that bots aren't counted
        user1.is_bot = True
        user1.save(update_fields=["is_bot"])
        self.assertEqual(get_latest_seat_count(realm), initial_count + 1)

        # Test that inactive users aren't counted
        do_deactivate_user(user2, acting_user=None)
        self.assertEqual(get_latest_seat_count(realm), initial_count)

        # Test guests
        # Adding a guest to a realm with a lot of members shouldn't change anything
        UserProfile.objects.create(
            realm=realm,
            email="user3@zulip.com",
            delivery_email="user3@zulip.com",
            role=UserProfile.ROLE_GUEST,
        )
        self.assertEqual(get_latest_seat_count(realm), initial_count)
        # Test 1 member and 5 guests
        realm = do_create_realm(string_id="second", name="second")
        UserProfile.objects.create(
            realm=realm, email="member@second.com", delivery_email="member@second.com"
        )
        for i in range(5):
            UserProfile.objects.create(
                realm=realm,
                email=f"guest{i}@second.com",
                delivery_email=f"guest{i}@second.com",
                role=UserProfile.ROLE_GUEST,
            )
        self.assertEqual(get_latest_seat_count(realm), 1)
        # Test 1 member and 6 guests
        UserProfile.objects.create(
            realm=realm,
            email="guest5@second.com",
            delivery_email="guest5@second.com",
            role=UserProfile.ROLE_GUEST,
        )
        self.assertEqual(get_latest_seat_count(realm), 2)

    def test_sign_string(self) -> None:
        string = "abc"
        signed_string, salt = sign_string(string)
        self.assertEqual(string, unsign_string(signed_string, salt))

        with self.assertRaises(signing.BadSignature):
            unsign_string(signed_string, "randomsalt")

    # This tests both the payment method string, and also is a very basic
    # test that the various upgrade paths involving non-standard payment
    # histories don't throw errors
    @mock_stripe()
    def test_payment_method_string(self, *mocks: Mock) -> None:
        pass
        # If you sign up with a card, we should show your card as the payment method
        # Already tested in test_initial_upgrade

        # If you pay by invoice, your payment method should be
        # "Billed by invoice", even if you have a card on file
        # user = self.example_user("hamlet")
        # billing_session = RealmBillingSession(user)
        # billing_session.create_stripe_customer()
        # self.login_user(user)
        # self.upgrade(invoice=True)
        # stripe_customer = stripe_get_customer(Customer.objects.get(realm=user.realm).stripe_customer_id)
        # self.assertEqual('Billed by invoice', payment_method_string(stripe_customer))

        # If you sign up with a card and then downgrade, we still have your
        # card on file, and should show it
        # TODO

    @mock_stripe()
    def test_replace_payment_method(self, *mocks: Mock) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)
        self.add_card_and_upgrade(user)
        # Create an open invoice
        customer = Customer.objects.first()
        assert customer is not None
        stripe_customer_id = customer.stripe_customer_id
        assert stripe_customer_id is not None
        stripe.InvoiceItem.create(amount=5000, currency="usd", customer=stripe_customer_id)
        stripe_invoice = stripe.Invoice.create(customer=stripe_customer_id)
        stripe.Invoice.finalize_invoice(stripe_invoice)
        RealmAuditLog.objects.filter(event_type=RealmAuditLog.STRIPE_CARD_CHANGED).delete()

        start_session_json_response = self.client_post(
            "/json/billing/session/start_card_update_session"
        )
        response_dict = self.assert_json_success(start_session_json_response)
        self.assert_details_of_valid_session_from_event_status_endpoint(
            response_dict["stripe_session_id"],
            {
                "type": "card_update_from_billing_page",
                "status": "created",
                "is_manual_license_management_upgrade_session": False,
            },
        )
        with self.assertRaises(stripe.error.CardError):
            # We don't have to handle this since the Stripe Checkout page would
            # ask Customer to enter a valid card number. trigger_stripe_checkout_session_completed_webhook
            # emulates what happens in the Stripe Checkout page. Adding this check mostly for coverage of
            # create_payment_method.
            self.trigger_stripe_checkout_session_completed_webhook(
                self.get_test_card_string(attaches_to_customer=False)
            )

        start_session_json_response = self.client_post(
            "/json/billing/session/start_card_update_session"
        )
        response_dict = self.assert_json_success(start_session_json_response)
        self.assert_details_of_valid_session_from_event_status_endpoint(
            response_dict["stripe_session_id"],
            {
                "type": "card_update_from_billing_page",
                "status": "created",
                "is_manual_license_management_upgrade_session": False,
            },
        )
        with self.assertLogs("corporate.stripe", "INFO") as m:
            self.trigger_stripe_checkout_session_completed_webhook(
                self.get_test_card_string(attaches_to_customer=True, charge_succeeds=False)
            )
            self.assertEqual(
                m.output[0],
                "INFO:corporate.stripe:Stripe card error: 402 card_error card_declined None",
            )
        response_dict = self.assert_json_success(start_session_json_response)
        self.assert_details_of_valid_session_from_event_status_endpoint(
            response_dict["stripe_session_id"],
            {
                "type": "card_update_from_billing_page",
                "status": "completed",
                "is_manual_license_management_upgrade_session": False,
                "event_handler": {
                    "status": "failed",
                    "error": {"message": "Your card was declined.", "description": "card error"},
                },
            },
        )

        response = self.client_get("/billing/")
        self.assert_in_success_response(["Visa ending in 0341"], response)
        assert RealmAuditLog.objects.filter(event_type=RealmAuditLog.STRIPE_CARD_CHANGED).exists()
        stripe_payment_methods = stripe.PaymentMethod.list(customer=stripe_customer_id, type="card")
        self.assert_length(stripe_payment_methods, 2)

        for stripe_payment_method in stripe_payment_methods:
            stripe.PaymentMethod.detach(stripe_payment_method.id)
        response = self.client_get("/billing/")
        self.assert_in_success_response(["No payment method on file."], response)

        start_session_json_response = self.client_post(
            "/json/billing/session/start_card_update_session"
        )
        self.assert_json_success(start_session_json_response)
        self.trigger_stripe_checkout_session_completed_webhook(
            self.get_test_card_string(
                attaches_to_customer=True, charge_succeeds=True, card_provider="mastercard"
            )
        )
        response_dict = self.assert_json_success(start_session_json_response)
        self.assert_details_of_valid_session_from_event_status_endpoint(
            response_dict["stripe_session_id"],
            {
                "type": "card_update_from_billing_page",
                "status": "completed",
                "is_manual_license_management_upgrade_session": False,
                "event_handler": {"status": "succeeded"},
            },
        )

        self.login_user(self.example_user("iago"))
        response = self.client_get(
            "/json/billing/event/status",
            {"stripe_session_id": response_dict["stripe_session_id"]},
        )
        self.assert_json_error_contains(
            response, "Must be a billing administrator or an organization owner"
        )

        self.login_user(self.example_user("hamlet"))
        response = self.client_get("/billing/")
        self.assert_in_success_response(["Mastercard ending in 4444"], response)
        self.assert_length(stripe.PaymentMethod.list(customer=stripe_customer_id, type="card"), 1)
        # Ideally we'd also test that we don't pay invoices with collection_method=='send_invoice'
        for stripe_invoice in stripe.Invoice.list(customer=stripe_customer_id):
            self.assertEqual(stripe_invoice.status, "paid")
        self.assertEqual(
            2, RealmAuditLog.objects.filter(event_type=RealmAuditLog.STRIPE_CARD_CHANGED).count()
        )

        # Test if manual license management upgrade session is created and is successfully recovered.
        start_session_json_response = self.client_post(
            "/json/upgrade/session/start_card_update_session", {"manual_license_management": "true"}
        )
        response_dict = self.assert_json_success(start_session_json_response)
        self.assert_details_of_valid_session_from_event_status_endpoint(
            response_dict["stripe_session_id"],
            {
                "type": "card_update_from_upgrade_page",
                "status": "created",
                "is_manual_license_management_upgrade_session": True,
            },
        )

    def test_downgrade(self) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)
        with time_machine.travel(self.now, tick=False):
            self.local_upgrade(
                self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
            )
        plan = get_current_plan_by_realm(user.realm)
        assert plan is not None
        self.assertEqual(plan.licenses(), self.seat_count)
        self.assertEqual(plan.licenses_at_next_renewal(), self.seat_count)
        with self.assertLogs("corporate.stripe", "INFO") as m:
            with time_machine.travel(self.now, tick=False):
                response = self.client_patch(
                    "/json/billing/plan", {"status": CustomerPlan.DOWNGRADE_AT_END_OF_CYCLE}
                )
                stripe_customer_id = Customer.objects.get(realm=user.realm).id
                new_plan = get_current_plan_by_realm(user.realm)
                assert new_plan is not None
                expected_log = f"INFO:corporate.stripe:Change plan status: Customer.id: {stripe_customer_id}, CustomerPlan.id: {new_plan.id}, status: {CustomerPlan.DOWNGRADE_AT_END_OF_CYCLE}"
                self.assertEqual(m.output[0], expected_log)
                self.assert_json_success(response)
        plan.refresh_from_db()
        self.assertEqual(plan.licenses(), self.seat_count)
        self.assertEqual(plan.licenses_at_next_renewal(), None)

        with time_machine.travel(self.now, tick=False):
            mock_customer = Mock(email=user.delivery_email)
            mock_customer.invoice_settings.default_payment_method = Mock(
                spec=stripe.PaymentMethod, type=Mock()
            )
            with patch("corporate.lib.stripe.stripe_get_customer", return_value=mock_customer):
                response = self.client_get("/billing/")
                self.assert_in_success_response(
                    [
                        "Your organization will be downgraded to <strong>Zulip Cloud Free</strong> at the end of the current billing",
                        "<strong>January 2, 2013</strong>",
                        "Reactivate subscription",
                    ],
                    response,
                )

        # Verify that we still write LicenseLedger rows during the remaining
        # part of the cycle
        billing_session = RealmBillingSession(user=user, realm=user.realm)
        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=20):
            billing_session.update_license_ledger_if_needed(self.now)
        self.assertEqual(
            LicenseLedger.objects.order_by("-id")
            .values_list("licenses", "licenses_at_next_renewal")
            .first(),
            (20, 20),
        )

        # Verify that we invoice them for the additional users
        mocked = self.setup_mocked_stripe(invoice_plans_as_needed, self.next_month)
        mocked["InvoiceItem"].create.assert_called_once()
        mocked["Invoice"].finalize_invoice.assert_called_once()
        mocked["Invoice"].create.assert_called_once()

        # Check that we downgrade properly if the cycle is over
        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=30):
            billing_session.update_license_ledger_if_needed(self.next_year)
        plan = CustomerPlan.objects.first()
        assert plan is not None
        self.assertEqual(get_realm("zulip").plan_type, Realm.PLAN_TYPE_LIMITED)
        self.assertEqual(plan.status, CustomerPlan.ENDED)
        self.assertEqual(
            LicenseLedger.objects.order_by("-id")
            .values_list("licenses", "licenses_at_next_renewal")
            .first(),
            (20, 20),
        )

        # Verify that we don't write LicenseLedger rows once we've downgraded
        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=40):
            billing_session.update_license_ledger_if_needed(self.next_year)
        self.assertEqual(
            LicenseLedger.objects.order_by("-id")
            .values_list("licenses", "licenses_at_next_renewal")
            .first(),
            (20, 20),
        )

        # Verify that we call invoice_plan once more after cycle end but
        # don't invoice them for users added after the cycle end
        plan = CustomerPlan.objects.first()
        assert plan is not None
        self.assertIsNotNone(plan.next_invoice_date)

        mocked = self.setup_mocked_stripe(
            invoice_plans_as_needed, self.next_year + timedelta(days=32)
        )
        mocked["InvoiceItem"].create.assert_not_called()
        mocked["Invoice"].finalize_invoice.assert_not_called()
        mocked["Invoice"].create.assert_not_called()

        # Check that we updated next_invoice_date in invoice_plan
        plan = CustomerPlan.objects.first()
        assert plan is not None
        self.assertIsNone(plan.next_invoice_date)

        # Check that we don't call invoice_plan after that final call
        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=50):
            billing_session.update_license_ledger_if_needed(self.next_year + timedelta(days=80))

        mocked = self.setup_mocked_stripe(
            invoice_plans_as_needed, self.next_year + timedelta(days=400)
        )
        mocked["InvoiceItem"].create.assert_not_called()
        mocked["Invoice"].finalize_invoice.assert_not_called()
        mocked["Invoice"].create.assert_not_called()

    @mock_stripe()
    def test_switch_from_monthly_plan_to_annual_plan_for_automatic_license_management(
        self, *mocks: Mock
    ) -> None:
        user = self.example_user("hamlet")

        self.login_user(user)
        self.add_card_and_upgrade(user, schedule="monthly")
        monthly_plan = get_current_plan_by_realm(user.realm)
        assert monthly_plan is not None
        self.assertEqual(monthly_plan.automanage_licenses, True)
        self.assertEqual(monthly_plan.billing_schedule, CustomerPlan.BILLING_SCHEDULE_MONTHLY)

        stripe_customer_id = Customer.objects.get(realm=user.realm).id
        new_plan = get_current_plan_by_realm(user.realm)
        assert new_plan is not None

        with self.assertLogs("corporate.stripe", "INFO") as m:
            with time_machine.travel(self.now, tick=False):
                response = self.client_patch(
                    "/json/billing/plan",
                    {"status": CustomerPlan.SWITCH_TO_ANNUAL_AT_END_OF_CYCLE},
                )
                expected_log = f"INFO:corporate.stripe:Change plan status: Customer.id: {stripe_customer_id}, CustomerPlan.id: {new_plan.id}, status: {CustomerPlan.SWITCH_TO_ANNUAL_AT_END_OF_CYCLE}"
                self.assertEqual(m.output[0], expected_log)
                self.assert_json_success(response)
        monthly_plan.refresh_from_db()
        self.assertEqual(monthly_plan.status, CustomerPlan.SWITCH_TO_ANNUAL_AT_END_OF_CYCLE)
        with time_machine.travel(self.now, tick=False):
            response = self.client_get("/billing/")
        self.assert_in_success_response(
            ["Your plan will switch to annual billing on February 2, 2012"], response
        )

        billing_session = RealmBillingSession(user=user, realm=user.realm)
        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=20):
            billing_session.update_license_ledger_if_needed(self.now)
        self.assertEqual(LicenseLedger.objects.filter(plan=monthly_plan).count(), 2)
        self.assertEqual(
            LicenseLedger.objects.order_by("-id")
            .values_list("licenses", "licenses_at_next_renewal")
            .first(),
            (20, 20),
        )

        with time_machine.travel(self.next_month, tick=False):
            with patch("corporate.lib.stripe.get_latest_seat_count", return_value=25):
                billing_session.update_license_ledger_if_needed(self.next_month)
        self.assertEqual(LicenseLedger.objects.filter(plan=monthly_plan).count(), 2)
        customer = get_customer_by_realm(user.realm)
        assert customer is not None
        self.assertEqual(CustomerPlan.objects.filter(customer=customer).count(), 2)
        monthly_plan.refresh_from_db()
        self.assertEqual(monthly_plan.status, CustomerPlan.ENDED)
        self.assertEqual(monthly_plan.next_invoice_date, self.next_month)
        annual_plan = get_current_plan_by_realm(user.realm)
        assert annual_plan is not None
        self.assertEqual(annual_plan.status, CustomerPlan.ACTIVE)
        self.assertEqual(annual_plan.billing_schedule, CustomerPlan.BILLING_SCHEDULE_ANNUAL)
        self.assertEqual(
            annual_plan.invoicing_status, CustomerPlan.INVOICING_STATUS_INITIAL_INVOICE_TO_BE_SENT
        )
        self.assertEqual(annual_plan.billing_cycle_anchor, self.next_month)
        self.assertEqual(annual_plan.next_invoice_date, self.next_month)
        self.assertEqual(annual_plan.invoiced_through, None)
        annual_ledger_entries = LicenseLedger.objects.filter(plan=annual_plan).order_by("id")
        self.assert_length(annual_ledger_entries, 2)
        self.assertEqual(annual_ledger_entries[0].is_renewal, True)
        self.assertEqual(
            annual_ledger_entries.values_list("licenses", "licenses_at_next_renewal")[0], (20, 20)
        )
        self.assertEqual(annual_ledger_entries[1].is_renewal, False)
        self.assertEqual(
            annual_ledger_entries.values_list("licenses", "licenses_at_next_renewal")[1], (25, 25)
        )
        audit_log = RealmAuditLog.objects.get(
            event_type=RealmAuditLog.CUSTOMER_SWITCHED_FROM_MONTHLY_TO_ANNUAL_PLAN
        )
        self.assertEqual(audit_log.realm, user.realm)
        self.assertEqual(audit_log.extra_data["monthly_plan_id"], monthly_plan.id)
        self.assertEqual(audit_log.extra_data["annual_plan_id"], annual_plan.id)

        invoice_plans_as_needed(self.next_month)

        annual_ledger_entries = LicenseLedger.objects.filter(plan=annual_plan).order_by("id")
        self.assert_length(annual_ledger_entries, 2)
        annual_plan.refresh_from_db()
        self.assertEqual(annual_plan.invoicing_status, CustomerPlan.INVOICING_STATUS_DONE)
        self.assertEqual(annual_plan.invoiced_through, annual_ledger_entries[1])
        self.assertEqual(annual_plan.billing_cycle_anchor, self.next_month)
        self.assertEqual(annual_plan.next_invoice_date, add_months(self.next_month, 1))
        monthly_plan.refresh_from_db()
        self.assertEqual(monthly_plan.next_invoice_date, None)

        assert customer.stripe_customer_id
        [invoice0, invoice1, invoice2] = iter(
            stripe.Invoice.list(customer=customer.stripe_customer_id)
        )

        [invoice_item0, invoice_item1] = iter(invoice0.lines)
        annual_plan_invoice_item_params = {
            "amount": 5 * 80 * 100,
            "description": "Additional license (Feb 2, 2012 - Feb 2, 2013)",
            "plan": None,
            "quantity": 5,
            "subscription": None,
            "discountable": False,
            "period": {
                "start": datetime_to_timestamp(self.next_month),
                "end": datetime_to_timestamp(add_months(self.next_month, 12)),
            },
        }
        for key, value in annual_plan_invoice_item_params.items():
            self.assertEqual(invoice_item0[key], value)

        annual_plan_invoice_item_params = {
            "amount": 20 * 80 * 100,
            "description": "Zulip Cloud Standard - renewal",
            "plan": None,
            "quantity": 20,
            "subscription": None,
            "discountable": False,
            "period": {
                "start": datetime_to_timestamp(self.next_month),
                "end": datetime_to_timestamp(add_months(self.next_month, 12)),
            },
        }
        for key, value in annual_plan_invoice_item_params.items():
            self.assertEqual(invoice_item1[key], value)

        [monthly_plan_invoice_item] = iter(invoice1.lines)
        monthly_plan_invoice_item_params = {
            "amount": 14 * 8 * 100,
            "description": "Additional license (Jan 2, 2012 - Feb 2, 2012)",
            "plan": None,
            "quantity": 14,
            "subscription": None,
            "discountable": False,
            "period": {
                "start": datetime_to_timestamp(self.now),
                "end": datetime_to_timestamp(self.next_month),
            },
        }
        for key, value in monthly_plan_invoice_item_params.items():
            self.assertEqual(monthly_plan_invoice_item[key], value)

        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=30):
            billing_session.update_license_ledger_if_needed(add_months(self.next_month, 1))
        invoice_plans_as_needed(add_months(self.next_month, 1))

        [invoice0, invoice1, invoice2, invoice3] = iter(
            stripe.Invoice.list(customer=customer.stripe_customer_id)
        )

        [monthly_plan_invoice_item] = iter(invoice0.lines)
        monthly_plan_invoice_item_params = {
            "amount": 5 * 7366,
            "description": "Additional license (Mar 2, 2012 - Feb 2, 2013)",
            "plan": None,
            "quantity": 5,
            "subscription": None,
            "discountable": False,
            "period": {
                "start": datetime_to_timestamp(add_months(self.next_month, 1)),
                "end": datetime_to_timestamp(add_months(self.next_month, 12)),
            },
        }
        for key, value in monthly_plan_invoice_item_params.items():
            self.assertEqual(monthly_plan_invoice_item[key], value)
        invoice_plans_as_needed(add_months(self.now, 13))

        [invoice0, invoice1, invoice2, invoice3, invoice4] = iter(
            stripe.Invoice.list(customer=customer.stripe_customer_id)
        )

        [invoice_item] = iter(invoice0.lines)
        annual_plan_invoice_item_params = {
            "amount": 30 * 80 * 100,
            "description": "Zulip Cloud Standard - renewal",
            "plan": None,
            "quantity": 30,
            "subscription": None,
            "discountable": False,
            "period": {
                "start": datetime_to_timestamp(add_months(self.next_month, 12)),
                "end": datetime_to_timestamp(add_months(self.next_month, 24)),
            },
        }
        for key, value in annual_plan_invoice_item_params.items():
            self.assertEqual(invoice_item[key], value)

    @mock_stripe()
    def test_switch_from_monthly_plan_to_annual_plan_for_manual_license_management(
        self, *mocks: Mock
    ) -> None:
        user = self.example_user("hamlet")
        num_licenses = 35

        self.login_user(user)
        self.add_card_and_upgrade(
            user, schedule="monthly", license_management="manual", licenses=num_licenses
        )
        monthly_plan = get_current_plan_by_realm(user.realm)
        assert monthly_plan is not None
        self.assertEqual(monthly_plan.automanage_licenses, False)
        self.assertEqual(monthly_plan.billing_schedule, CustomerPlan.BILLING_SCHEDULE_MONTHLY)
        stripe_customer_id = Customer.objects.get(realm=user.realm).id
        new_plan = get_current_plan_by_realm(user.realm)
        assert new_plan is not None
        with self.assertLogs("corporate.stripe", "INFO") as m:
            with time_machine.travel(self.now, tick=False):
                response = self.client_patch(
                    "/json/billing/plan",
                    {"status": CustomerPlan.SWITCH_TO_ANNUAL_AT_END_OF_CYCLE},
                )
                self.assertEqual(
                    m.output[0],
                    f"INFO:corporate.stripe:Change plan status: Customer.id: {stripe_customer_id}, CustomerPlan.id: {new_plan.id}, status: {CustomerPlan.SWITCH_TO_ANNUAL_AT_END_OF_CYCLE}",
                )
                self.assert_json_success(response)
        monthly_plan.refresh_from_db()
        self.assertEqual(monthly_plan.status, CustomerPlan.SWITCH_TO_ANNUAL_AT_END_OF_CYCLE)
        with time_machine.travel(self.now, tick=False):
            response = self.client_get("/billing/")
        self.assert_in_success_response(
            ["Your plan will switch to annual billing on February 2, 2012"], response
        )

        invoice_plans_as_needed(self.next_month)

        self.assertEqual(LicenseLedger.objects.filter(plan=monthly_plan).count(), 1)
        customer = get_customer_by_realm(user.realm)
        assert customer is not None
        self.assertEqual(CustomerPlan.objects.filter(customer=customer).count(), 2)
        monthly_plan.refresh_from_db()
        self.assertEqual(monthly_plan.status, CustomerPlan.ENDED)
        self.assertEqual(monthly_plan.next_invoice_date, None)
        annual_plan = get_current_plan_by_realm(user.realm)
        assert annual_plan is not None
        self.assertEqual(annual_plan.status, CustomerPlan.ACTIVE)
        self.assertEqual(annual_plan.billing_schedule, CustomerPlan.BILLING_SCHEDULE_ANNUAL)
        self.assertEqual(
            annual_plan.invoicing_status, CustomerPlan.INVOICING_STATUS_INITIAL_INVOICE_TO_BE_SENT
        )
        self.assertEqual(annual_plan.billing_cycle_anchor, self.next_month)
        self.assertEqual(annual_plan.next_invoice_date, self.next_month)
        annual_ledger_entries = LicenseLedger.objects.filter(plan=annual_plan).order_by("id")
        self.assert_length(annual_ledger_entries, 1)
        self.assertEqual(annual_ledger_entries[0].is_renewal, True)
        self.assertEqual(
            annual_ledger_entries.values_list("licenses", "licenses_at_next_renewal")[0],
            (num_licenses, num_licenses),
        )
        self.assertEqual(annual_plan.invoiced_through, None)

        # First call of invoice_plans_as_needed creates the new plan. Second call
        # calls invoice_plan on the newly created plan.
        invoice_plans_as_needed(self.next_month + timedelta(days=1))

        annual_plan.refresh_from_db()
        self.assertEqual(annual_plan.invoiced_through, annual_ledger_entries[0])
        self.assertEqual(annual_plan.next_invoice_date, add_months(self.next_month, 12))
        self.assertEqual(annual_plan.invoicing_status, CustomerPlan.INVOICING_STATUS_DONE)

        assert customer.stripe_customer_id
        [invoice0, invoice1] = iter(stripe.Invoice.list(customer=customer.stripe_customer_id))

        [invoice_item] = iter(invoice0.lines)
        annual_plan_invoice_item_params = {
            "amount": num_licenses * 80 * 100,
            "description": "Zulip Cloud Standard - renewal",
            "plan": None,
            "quantity": num_licenses,
            "subscription": None,
            "discountable": False,
            "period": {
                "start": datetime_to_timestamp(self.next_month),
                "end": datetime_to_timestamp(add_months(self.next_month, 12)),
            },
        }
        for key, value in annual_plan_invoice_item_params.items():
            self.assertEqual(invoice_item[key], value)

        with patch("corporate.lib.stripe.BillingSession.invoice_plan") as m:
            invoice_plans_as_needed(add_months(self.now, 2))
            m.assert_not_called()

        invoice_plans_as_needed(add_months(self.now, 13))

        [invoice0, invoice1, invoice2] = iter(
            stripe.Invoice.list(customer=customer.stripe_customer_id)
        )

        [invoice_item] = iter(invoice0.lines)
        annual_plan_invoice_item_params = {
            "amount": num_licenses * 80 * 100,
            "description": "Zulip Cloud Standard - renewal",
            "plan": None,
            "quantity": num_licenses,
            "subscription": None,
            "discountable": False,
            "period": {
                "start": datetime_to_timestamp(add_months(self.next_month, 12)),
                "end": datetime_to_timestamp(add_months(self.next_month, 24)),
            },
        }
        for key, value in annual_plan_invoice_item_params.items():
            self.assertEqual(invoice_item[key], value)

    @mock_stripe()
    def test_switch_from_annual_plan_to_monthly_plan_for_automatic_license_management(
        self, *mocks: Mock
    ) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)
        self.add_card_and_upgrade(user, schedule="annual")
        annual_plan = get_current_plan_by_realm(user.realm)
        assert annual_plan is not None
        self.assertEqual(annual_plan.automanage_licenses, True)
        self.assertEqual(annual_plan.billing_schedule, CustomerPlan.BILLING_SCHEDULE_ANNUAL)

        stripe_customer_id = Customer.objects.get(realm=user.realm).id
        new_plan = get_current_plan_by_realm(user.realm)
        assert new_plan is not None

        assert self.now is not None
        with self.assertLogs("corporate.stripe", "INFO") as m:
            with time_machine.travel(self.now, tick=False):
                response = self.client_patch(
                    "/json/billing/plan",
                    {"status": CustomerPlan.SWITCH_TO_MONTHLY_AT_END_OF_CYCLE},
                )
                expected_log = f"INFO:corporate.stripe:Change plan status: Customer.id: {stripe_customer_id}, CustomerPlan.id: {new_plan.id}, status: {CustomerPlan.SWITCH_TO_MONTHLY_AT_END_OF_CYCLE}"
                self.assertEqual(m.output[0], expected_log)
                self.assert_json_success(response)
        annual_plan.refresh_from_db()
        self.assertEqual(annual_plan.status, CustomerPlan.SWITCH_TO_MONTHLY_AT_END_OF_CYCLE)
        with time_machine.travel(self.now, tick=False):
            response = self.client_get("/billing/")
        self.assert_in_success_response(
            ["Your plan will switch to monthly billing on January 2, 2013"], response
        )

        billing_session = RealmBillingSession(user=user, realm=user.realm)
        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=20):
            billing_session.update_license_ledger_if_needed(self.now)
        self.assertEqual(LicenseLedger.objects.filter(plan=annual_plan).count(), 2)
        self.assertEqual(
            LicenseLedger.objects.order_by("-id")
            .values_list("licenses", "licenses_at_next_renewal")
            .first(),
            (20, 20),
        )

        # Check that we don't switch to monthly plan at next invoice date (which is used to charge user for
        # additional licenses) but at the end of current billing cycle.
        self.assertEqual(annual_plan.next_invoice_date, self.next_month)
        assert annual_plan.next_invoice_date is not None
        with time_machine.travel(annual_plan.next_invoice_date, tick=False):
            with patch("corporate.lib.stripe.get_latest_seat_count", return_value=25):
                billing_session.update_license_ledger_if_needed(annual_plan.next_invoice_date)

        annual_plan.refresh_from_db()
        self.assertEqual(annual_plan.status, CustomerPlan.SWITCH_TO_MONTHLY_AT_END_OF_CYCLE)
        self.assertEqual(annual_plan.next_invoice_date, self.next_month)
        self.assertEqual(annual_plan.billing_schedule, CustomerPlan.BILLING_SCHEDULE_ANNUAL)
        self.assertEqual(LicenseLedger.objects.filter(plan=annual_plan).count(), 3)

        invoice_plans_as_needed(self.next_month + timedelta(days=1))

        annual_plan.refresh_from_db()
        self.assertEqual(annual_plan.next_invoice_date, add_months(self.next_month, 1))
        self.assertEqual(annual_plan.invoicing_status, CustomerPlan.INVOICING_STATUS_DONE)
        self.assertEqual(LicenseLedger.objects.filter(plan=annual_plan).count(), 3)

        customer = get_customer_by_realm(user.realm)
        assert customer is not None
        assert customer.stripe_customer_id
        [invoice0, invoice1] = iter(stripe.Invoice.list(customer=customer.stripe_customer_id))
        [invoice_item1, invoice_item2] = iter(invoice0.lines)
        annual_plan_invoice_item_params = {
            "amount": 7322 * 5,
            "description": "Additional license (Feb 2, 2012 - Jan 2, 2013)",
            "plan": None,
            "quantity": 5,
            "subscription": None,
            "discountable": False,
            "period": {
                "start": datetime_to_timestamp(self.next_month),
                "end": datetime_to_timestamp(self.next_year),
            },
        }

        for key, value in annual_plan_invoice_item_params.items():
            self.assertEqual(invoice_item1[key], value)

        annual_plan_invoice_item_params = {
            "amount": 14 * 80 * 1 * 100,
            "description": "Additional license (Jan 2, 2012 - Jan 2, 2013)",
            "plan": None,
            "quantity": 14,
            "subscription": None,
            "discountable": False,
            "period": {
                "start": datetime_to_timestamp(self.now),
                "end": datetime_to_timestamp(self.next_year),
            },
        }

        for key, value in annual_plan_invoice_item_params.items():
            self.assertEqual(invoice_item2[key], value)

        # Check that we switch to monthly plan at the end of current billing cycle.
        with time_machine.travel(self.next_year, tick=False):
            with patch("corporate.lib.stripe.get_latest_seat_count", return_value=25):
                billing_session.update_license_ledger_if_needed(self.next_year)
        self.assertEqual(LicenseLedger.objects.filter(plan=annual_plan).count(), 3)
        customer = get_customer_by_realm(user.realm)
        assert customer is not None
        annual_plan.refresh_from_db()
        self.assertEqual(annual_plan.status, CustomerPlan.ENDED)
        self.assertEqual(annual_plan.next_invoice_date, add_months(self.next_month, 1))
        monthly_plan = get_current_plan_by_realm(user.realm)
        assert monthly_plan is not None
        self.assertEqual(monthly_plan.status, CustomerPlan.ACTIVE)
        self.assertEqual(monthly_plan.billing_schedule, CustomerPlan.BILLING_SCHEDULE_MONTHLY)
        self.assertEqual(
            monthly_plan.invoicing_status, CustomerPlan.INVOICING_STATUS_INITIAL_INVOICE_TO_BE_SENT
        )
        self.assertEqual(monthly_plan.billing_cycle_anchor, self.next_year)
        self.assertEqual(monthly_plan.next_invoice_date, self.next_year)
        self.assertEqual(monthly_plan.invoiced_through, None)
        monthly_ledger_entries = LicenseLedger.objects.filter(plan=monthly_plan).order_by("id")
        self.assert_length(monthly_ledger_entries, 2)
        self.assertEqual(monthly_ledger_entries[0].is_renewal, True)
        self.assertEqual(
            monthly_ledger_entries.values_list("licenses", "licenses_at_next_renewal")[0], (25, 25)
        )
        self.assertEqual(monthly_ledger_entries[1].is_renewal, False)
        self.assertEqual(
            monthly_ledger_entries.values_list("licenses", "licenses_at_next_renewal")[1], (25, 25)
        )
        audit_log = RealmAuditLog.objects.get(
            event_type=RealmAuditLog.CUSTOMER_SWITCHED_FROM_ANNUAL_TO_MONTHLY_PLAN
        )
        self.assertEqual(audit_log.realm, user.realm)
        self.assertEqual(audit_log.extra_data["annual_plan_id"], annual_plan.id)
        self.assertEqual(audit_log.extra_data["monthly_plan_id"], monthly_plan.id)

        invoice_plans_as_needed(self.next_year)

        monthly_ledger_entries = LicenseLedger.objects.filter(plan=monthly_plan).order_by("id")
        self.assert_length(monthly_ledger_entries, 2)
        monthly_plan.refresh_from_db()
        self.assertEqual(monthly_plan.invoicing_status, CustomerPlan.INVOICING_STATUS_DONE)
        self.assertEqual(monthly_plan.invoiced_through, monthly_ledger_entries[1])
        self.assertEqual(monthly_plan.billing_cycle_anchor, self.next_year)
        self.assertEqual(monthly_plan.next_invoice_date, add_months(self.next_year, 1))
        annual_plan.refresh_from_db()
        self.assertEqual(annual_plan.next_invoice_date, None)

        assert customer.stripe_customer_id
        [invoice0, invoice1, invoice2] = iter(
            stripe.Invoice.list(customer=customer.stripe_customer_id)
        )

        [invoice_item0] = iter(invoice0.lines)

        monthly_plan_invoice_item_params = {
            "amount": 25 * 8 * 100,
            "description": "Zulip Cloud Standard - renewal",
            "plan": None,
            "quantity": 25,
            "subscription": None,
            "discountable": False,
            "period": {
                "start": datetime_to_timestamp(self.next_year),
                "end": datetime_to_timestamp(add_months(self.next_year, 1)),
            },
        }
        for key, value in monthly_plan_invoice_item_params.items():
            self.assertEqual(invoice_item0[key], value)

        with time_machine.travel(self.now, tick=False):
            response = self.client_get("/billing/")
        self.assert_not_in_success_response(
            ["Your plan will switch to annual billing on February 2, 2012"], response
        )

    def test_reupgrade_after_plan_status_changed_to_downgrade_at_end_of_cycle(self) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)
        with time_machine.travel(self.now, tick=False):
            self.local_upgrade(
                self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
            )
        with self.assertLogs("corporate.stripe", "INFO") as m:
            with time_machine.travel(self.now, tick=False):
                response = self.client_patch(
                    "/json/billing/plan", {"status": CustomerPlan.DOWNGRADE_AT_END_OF_CYCLE}
                )
                stripe_customer_id = Customer.objects.get(realm=user.realm).id
                new_plan = get_current_plan_by_realm(user.realm)
                assert new_plan is not None
                expected_log = f"INFO:corporate.stripe:Change plan status: Customer.id: {stripe_customer_id}, CustomerPlan.id: {new_plan.id}, status: {CustomerPlan.DOWNGRADE_AT_END_OF_CYCLE}"
                self.assertEqual(m.output[0], expected_log)
                self.assert_json_success(response)
        plan = CustomerPlan.objects.first()
        assert plan is not None
        self.assertEqual(plan.status, CustomerPlan.DOWNGRADE_AT_END_OF_CYCLE)
        with self.assertLogs("corporate.stripe", "INFO") as m:
            with time_machine.travel(self.now, tick=False):
                response = self.client_patch("/json/billing/plan", {"status": CustomerPlan.ACTIVE})
                expected_log = f"INFO:corporate.stripe:Change plan status: Customer.id: {stripe_customer_id}, CustomerPlan.id: {new_plan.id}, status: {CustomerPlan.ACTIVE}"
                self.assertEqual(m.output[0], expected_log)
                self.assert_json_success(response)
        plan = CustomerPlan.objects.first()
        assert plan is not None
        self.assertEqual(plan.status, CustomerPlan.ACTIVE)

    @patch("stripe.Invoice.create")
    @patch("stripe.Invoice.finalize_invoice")
    @patch("stripe.InvoiceItem.create")
    def test_downgrade_during_invoicing(self, *mocks: Mock) -> None:
        # The difference between this test and test_downgrade is that
        # CustomerPlan.status is DOWNGRADE_AT_END_OF_CYCLE rather than ENDED
        # when we call invoice_plans_as_needed
        # This test is essentially checking that we call make_end_of_cycle_updates_if_needed
        # during the invoicing process.
        user = self.example_user("hamlet")
        self.login_user(user)
        with time_machine.travel(self.now, tick=False):
            self.local_upgrade(
                self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
            )
        with self.assertLogs("corporate.stripe", "INFO") as m:
            stripe_customer_id = Customer.objects.get(realm=user.realm).id
            new_plan = get_current_plan_by_realm(user.realm)
            assert new_plan is not None
            with time_machine.travel(self.now, tick=False):
                self.client_patch(
                    "/json/billing/plan", {"status": CustomerPlan.DOWNGRADE_AT_END_OF_CYCLE}
                )
            expected_log = f"INFO:corporate.stripe:Change plan status: Customer.id: {stripe_customer_id}, CustomerPlan.id: {new_plan.id}, status: {CustomerPlan.DOWNGRADE_AT_END_OF_CYCLE}"
            self.assertEqual(m.output[0], expected_log)

        plan = CustomerPlan.objects.first()
        assert plan is not None
        self.assertIsNotNone(plan.next_invoice_date)
        self.assertEqual(plan.status, CustomerPlan.DOWNGRADE_AT_END_OF_CYCLE)
        invoice_plans_as_needed(self.next_year)
        plan = CustomerPlan.objects.first()
        assert plan is not None
        self.assertIsNone(plan.next_invoice_date)
        self.assertEqual(plan.status, CustomerPlan.ENDED)

    @mock_stripe()
    def test_switch_now_free_trial_from_monthly_to_annual(self, *mocks: Mock) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)

        free_trial_end_date = self.now + timedelta(days=60)
        with self.settings(CLOUD_FREE_TRIAL_DAYS=60):
            with time_machine.travel(self.now, tick=False):
                self.add_card_and_upgrade(user, schedule="monthly")
                plan = CustomerPlan.objects.get()
                self.assertEqual(plan.next_invoice_date, free_trial_end_date)
                self.assertEqual(get_realm("zulip").plan_type, Realm.PLAN_TYPE_STANDARD)
                self.assertEqual(plan.status, CustomerPlan.FREE_TRIAL)

                customer = get_customer_by_realm(user.realm)
                assert customer is not None
                result = self.client_patch(
                    "/json/billing/plan",
                    {
                        "status": CustomerPlan.FREE_TRIAL,
                        "schedule": CustomerPlan.BILLING_SCHEDULE_ANNUAL,
                    },
                )
                self.assert_json_success(result)

                plan.refresh_from_db()
                self.assertEqual(plan.status, CustomerPlan.ENDED)

                plan = CustomerPlan.objects.get(
                    customer=customer,
                    automanage_licenses=True,
                    price_per_license=8000,
                    fixed_price=None,
                    discount=None,
                    billing_cycle_anchor=self.now,
                    billing_schedule=CustomerPlan.BILLING_SCHEDULE_ANNUAL,
                    invoiced_through=None,
                    next_invoice_date=free_trial_end_date,
                    tier=CustomerPlan.TIER_CLOUD_STANDARD,
                    status=CustomerPlan.FREE_TRIAL,
                    charge_automatically=True,
                )
                LicenseLedger.objects.get(
                    plan=plan,
                    is_renewal=True,
                    event_time=self.now,
                    licenses=self.seat_count,
                    licenses_at_next_renewal=self.seat_count,
                )

                realm_audit_log = RealmAuditLog.objects.filter(
                    event_type=RealmAuditLog.CUSTOMER_SWITCHED_FROM_MONTHLY_TO_ANNUAL_PLAN
                ).last()
                assert realm_audit_log is not None

    @mock_stripe()
    def test_switch_now_free_trial_from_annual_to_monthly(self, *mocks: Mock) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)

        free_trial_end_date = self.now + timedelta(days=60)
        with self.settings(CLOUD_FREE_TRIAL_DAYS=60):
            with time_machine.travel(self.now, tick=False):
                self.add_card_and_upgrade(user, schedule="annual")
                plan = CustomerPlan.objects.get()
                self.assertEqual(plan.next_invoice_date, free_trial_end_date)
                self.assertEqual(get_realm("zulip").plan_type, Realm.PLAN_TYPE_STANDARD)
                self.assertEqual(plan.status, CustomerPlan.FREE_TRIAL)

                customer = get_customer_by_realm(user.realm)
                assert customer is not None
                result = self.client_patch(
                    "/json/billing/plan",
                    {
                        "status": CustomerPlan.FREE_TRIAL,
                        "schedule": CustomerPlan.BILLING_SCHEDULE_MONTHLY,
                    },
                )
                self.assert_json_success(result)
                plan.refresh_from_db()
                self.assertEqual(plan.status, CustomerPlan.ENDED)

                plan = CustomerPlan.objects.get(
                    customer=customer,
                    automanage_licenses=True,
                    price_per_license=800,
                    fixed_price=None,
                    discount=None,
                    billing_cycle_anchor=self.now,
                    billing_schedule=CustomerPlan.BILLING_SCHEDULE_MONTHLY,
                    invoiced_through=None,
                    next_invoice_date=free_trial_end_date,
                    tier=CustomerPlan.TIER_CLOUD_STANDARD,
                    status=CustomerPlan.FREE_TRIAL,
                    charge_automatically=True,
                )
                LicenseLedger.objects.get(
                    plan=plan,
                    is_renewal=True,
                    event_time=self.now,
                    licenses=self.seat_count,
                    licenses_at_next_renewal=self.seat_count,
                )

                realm_audit_log = RealmAuditLog.objects.filter(
                    event_type=RealmAuditLog.CUSTOMER_SWITCHED_FROM_ANNUAL_TO_MONTHLY_PLAN
                ).last()
                assert realm_audit_log is not None

    def test_end_free_trial(self) -> None:
        user = self.example_user("hamlet")

        free_trial_end_date = self.now + timedelta(days=60)
        with self.settings(CLOUD_FREE_TRIAL_DAYS=60):
            with time_machine.travel(self.now, tick=False):
                self.local_upgrade(
                    self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, False, True
                )

            plan = CustomerPlan.objects.get()
            self.assertEqual(plan.next_invoice_date, free_trial_end_date)
            self.assertEqual(get_realm("zulip").plan_type, Realm.PLAN_TYPE_STANDARD)
            self.assertEqual(plan.status, CustomerPlan.FREE_TRIAL)

            # Add some extra users before the realm is deactivated
            billing_session = RealmBillingSession(user=user, realm=user.realm)
            with patch("corporate.lib.stripe.get_latest_seat_count", return_value=21):
                billing_session.update_license_ledger_if_needed(self.now)

            last_ledger_entry = LicenseLedger.objects.order_by("id").last()
            assert last_ledger_entry is not None
            self.assertEqual(last_ledger_entry.licenses, 21)
            self.assertEqual(last_ledger_entry.licenses_at_next_renewal, 21)

            self.login_user(user)

            with time_machine.travel(self.now, tick=False):
                self.client_patch("/json/billing/plan", {"status": CustomerPlan.ENDED})

            plan.refresh_from_db()
            self.assertEqual(get_realm("zulip").plan_type, Realm.PLAN_TYPE_LIMITED)
            self.assertEqual(plan.status, CustomerPlan.ENDED)
            self.assertEqual(plan.invoiced_through, last_ledger_entry)
            self.assertIsNone(plan.next_invoice_date)

            self.login_user(user)
            response = self.client_get("/billing/")
            self.assertEqual(response.status_code, 302)
            self.assertEqual("/plans/", response["Location"])

            # The extra users added in the final month are not charged
            with patch("corporate.lib.stripe.BillingSession.invoice_plan") as mocked:
                invoice_plans_as_needed(self.next_month)
            mocked.assert_not_called()

            # The plan is not renewed after an year
            with patch("corporate.lib.stripe.BillingSession.invoice_plan") as mocked:
                invoice_plans_as_needed(self.next_year)
            mocked.assert_not_called()

    def test_downgrade_at_end_of_free_trial(self) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)

        free_trial_end_date = self.now + timedelta(days=60)
        with self.settings(CLOUD_FREE_TRIAL_DAYS=60):
            with time_machine.travel(self.now, tick=False):
                self.local_upgrade(
                    self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, False, True
                )
            plan = get_current_plan_by_realm(user.realm)
            assert plan is not None
            self.assertEqual(plan.next_invoice_date, free_trial_end_date)
            self.assertEqual(get_realm("zulip").plan_type, Realm.PLAN_TYPE_STANDARD)
            self.assertEqual(plan.status, CustomerPlan.FREE_TRIAL)
            self.assertEqual(plan.licenses(), self.seat_count)
            self.assertEqual(plan.licenses_at_next_renewal(), self.seat_count)

            # Schedule downgrade
            with self.assertLogs("corporate.stripe", "INFO") as m:
                with time_machine.travel(self.now, tick=False):
                    response = self.client_patch(
                        "/json/billing/plan",
                        {"status": CustomerPlan.DOWNGRADE_AT_END_OF_FREE_TRIAL},
                    )
                    stripe_customer_id = Customer.objects.get(realm=user.realm).id
                    new_plan = get_current_plan_by_realm(user.realm)
                    assert new_plan is not None
                    expected_log = f"INFO:corporate.stripe:Change plan status: Customer.id: {stripe_customer_id}, CustomerPlan.id: {new_plan.id}, status: {CustomerPlan.DOWNGRADE_AT_END_OF_FREE_TRIAL}"
                    self.assertEqual(m.output[0], expected_log)
                    self.assert_json_success(response)
            plan.refresh_from_db()
            self.assertEqual(plan.next_invoice_date, free_trial_end_date)
            self.assertEqual(get_realm("zulip").plan_type, Realm.PLAN_TYPE_STANDARD)
            self.assertEqual(plan.status, CustomerPlan.DOWNGRADE_AT_END_OF_FREE_TRIAL)
            self.assertEqual(plan.licenses(), self.seat_count)
            self.assertEqual(plan.licenses_at_next_renewal(), None)

            with time_machine.travel(self.now, tick=False):
                mock_customer = Mock(email=user.delivery_email)
                mock_customer.invoice_settings.default_payment_method = Mock(
                    spec=stripe.PaymentMethod, type=Mock()
                )
                with patch("corporate.lib.stripe.stripe_get_customer", return_value=mock_customer):
                    response = self.client_get("/billing/")
                    self.assert_in_success_response(
                        [
                            "Your organization will be downgraded to <strong>Zulip Cloud Free</strong> at the end of the free trial",
                            "<strong>March 2, 2012</strong>",
                        ],
                        response,
                    )

            billing_session = RealmBillingSession(user=user, realm=user.realm)
            # Verify that we still write LicenseLedger rows during the remaining
            # part of the cycle
            with patch("corporate.lib.stripe.get_latest_seat_count", return_value=20):
                billing_session.update_license_ledger_if_needed(self.now)
            self.assertEqual(
                LicenseLedger.objects.order_by("-id")
                .values_list("licenses", "licenses_at_next_renewal")
                .first(),
                (20, 20),
            )

            # Verify that we don't invoice them for the additional users during free trial.
            mocked = self.setup_mocked_stripe(invoice_plans_as_needed, self.next_month)
            mocked["InvoiceItem"].create.assert_not_called()
            mocked["Invoice"].finalize_invoice.assert_not_called()
            mocked["Invoice"].create.assert_not_called()

            # Check that we downgrade properly if the cycle is over
            with patch("corporate.lib.stripe.get_latest_seat_count", return_value=30):
                billing_session.update_license_ledger_if_needed(free_trial_end_date)
            plan = CustomerPlan.objects.first()
            assert plan is not None
            self.assertIsNone(plan.next_invoice_date)
            self.assertEqual(plan.status, CustomerPlan.ENDED)
            self.assertEqual(get_realm("zulip").plan_type, Realm.PLAN_TYPE_LIMITED)
            self.assertEqual(
                LicenseLedger.objects.order_by("-id")
                .values_list("licenses", "licenses_at_next_renewal")
                .first(),
                (20, 20),
            )

            # Verify that we don't write LicenseLedger rows once we've downgraded
            with patch("corporate.lib.stripe.get_latest_seat_count", return_value=40):
                billing_session.update_license_ledger_if_needed(self.next_year)
            self.assertEqual(
                LicenseLedger.objects.order_by("-id")
                .values_list("licenses", "licenses_at_next_renewal")
                .first(),
                (20, 20),
            )

            self.login_user(user)
            response = self.client_get("/billing/")
            self.assertEqual(response.status_code, 302)
            self.assertEqual("/plans/", response["Location"])

            # The extra users added in the final month are not charged
            with patch("corporate.lib.stripe.BillingSession.invoice_plan") as mocked:
                invoice_plans_as_needed(self.next_month)
            mocked.assert_not_called()

            # The plan is not renewed after an year
            with patch("corporate.lib.stripe.BillingSession.invoice_plan") as mocked:
                invoice_plans_as_needed(self.next_year)
            mocked.assert_not_called()

    def test_cancel_downgrade_at_end_of_free_trial(self) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)

        free_trial_end_date = self.now + timedelta(days=60)
        with self.settings(CLOUD_FREE_TRIAL_DAYS=60):
            with time_machine.travel(self.now, tick=False):
                self.local_upgrade(
                    self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, False, True
                )
            plan = get_current_plan_by_realm(user.realm)
            assert plan is not None
            self.assertEqual(plan.next_invoice_date, free_trial_end_date)
            self.assertEqual(get_realm("zulip").plan_type, Realm.PLAN_TYPE_STANDARD)
            self.assertEqual(plan.status, CustomerPlan.FREE_TRIAL)
            self.assertEqual(plan.licenses(), self.seat_count)
            self.assertEqual(plan.licenses_at_next_renewal(), self.seat_count)

            # Schedule downgrade
            with self.assertLogs("corporate.stripe", "INFO") as m:
                with time_machine.travel(self.now, tick=False):
                    response = self.client_patch(
                        "/json/billing/plan",
                        {"status": CustomerPlan.DOWNGRADE_AT_END_OF_FREE_TRIAL},
                    )
                    stripe_customer_id = Customer.objects.get(realm=user.realm).id
                    new_plan = get_current_plan_by_realm(user.realm)
                    assert new_plan is not None
                    expected_log = f"INFO:corporate.stripe:Change plan status: Customer.id: {stripe_customer_id}, CustomerPlan.id: {new_plan.id}, status: {CustomerPlan.DOWNGRADE_AT_END_OF_FREE_TRIAL}"
                    self.assertEqual(m.output[0], expected_log)
                    self.assert_json_success(response)
            plan.refresh_from_db()
            self.assertEqual(plan.next_invoice_date, free_trial_end_date)
            self.assertEqual(get_realm("zulip").plan_type, Realm.PLAN_TYPE_STANDARD)
            self.assertEqual(plan.status, CustomerPlan.DOWNGRADE_AT_END_OF_FREE_TRIAL)
            self.assertEqual(plan.licenses(), self.seat_count)
            self.assertEqual(plan.licenses_at_next_renewal(), None)

            # Cancel downgrade
            with self.assertLogs("corporate.stripe", "INFO") as m:
                with time_machine.travel(self.now, tick=False):
                    response = self.client_patch(
                        "/json/billing/plan", {"status": CustomerPlan.FREE_TRIAL}
                    )
                    stripe_customer_id = Customer.objects.get(realm=user.realm).id
                    new_plan = get_current_plan_by_realm(user.realm)
                    assert new_plan is not None
                    expected_log = f"INFO:corporate.stripe:Change plan status: Customer.id: {stripe_customer_id}, CustomerPlan.id: {new_plan.id}, status: {CustomerPlan.FREE_TRIAL}"
                    self.assertEqual(m.output[0], expected_log)
                    self.assert_json_success(response)
            plan.refresh_from_db()
            self.assertEqual(plan.next_invoice_date, free_trial_end_date)
            self.assertEqual(get_realm("zulip").plan_type, Realm.PLAN_TYPE_STANDARD)
            self.assertEqual(plan.status, CustomerPlan.FREE_TRIAL)
            self.assertEqual(plan.licenses(), self.seat_count)
            self.assertEqual(plan.licenses_at_next_renewal(), self.seat_count)

    def test_reupgrade_by_billing_admin_after_downgrade(self) -> None:
        user = self.example_user("hamlet")

        with time_machine.travel(self.now, tick=False):
            self.local_upgrade(
                self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
            )

        self.login_user(user)
        with self.assertLogs("corporate.stripe", "INFO") as m:
            with time_machine.travel(self.now, tick=False):
                self.client_patch(
                    "/json/billing/plan", {"status": CustomerPlan.DOWNGRADE_AT_END_OF_CYCLE}
                )
            stripe_customer_id = Customer.objects.get(realm=user.realm).id
            new_plan = get_current_plan_by_realm(user.realm)
            assert new_plan is not None
            expected_log = f"INFO:corporate.stripe:Change plan status: Customer.id: {stripe_customer_id}, CustomerPlan.id: {new_plan.id}, status: {CustomerPlan.DOWNGRADE_AT_END_OF_CYCLE}"
            self.assertEqual(m.output[0], expected_log)

        with self.assertRaises(BillingError) as context, self.assertLogs(
            "corporate.stripe", "WARNING"
        ) as m:
            with time_machine.travel(self.now, tick=False):
                self.local_upgrade(
                    self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
                )
        self.assertEqual(
            m.output[0],
            "WARNING:corporate.stripe:Upgrade of <Realm: zulip 2> (with stripe_customer_id: cus_123) failed because of existing active plan.",
        )
        self.assertEqual(
            context.exception.error_description, "subscribing with existing subscription"
        )

        invoice_plans_as_needed(self.next_year)

        response = self.client_get("/billing/")
        self.assertEqual(response.status_code, 302)
        self.assertEqual("/plans/", response["Location"])

        with time_machine.travel(self.next_year, tick=False):
            self.local_upgrade(
                self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
            )

        self.assertEqual(Customer.objects.count(), 1)
        self.assertEqual(CustomerPlan.objects.count(), 2)

        current_plan = CustomerPlan.objects.all().order_by("id").last()
        assert current_plan is not None
        next_invoice_date = add_months(self.next_year, 1)
        self.assertEqual(current_plan.next_invoice_date, next_invoice_date)
        self.assertEqual(get_realm("zulip").plan_type, Realm.PLAN_TYPE_STANDARD)
        self.assertEqual(current_plan.status, CustomerPlan.ACTIVE)

        old_plan = CustomerPlan.objects.all().order_by("id").first()
        assert old_plan is not None
        self.assertEqual(old_plan.next_invoice_date, None)
        self.assertEqual(old_plan.status, CustomerPlan.ENDED)

    @mock_stripe()
    def test_update_licenses_of_manual_plan_from_billing_page(self, *mocks: Mock) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)

        with time_machine.travel(self.now, tick=False):
            self.upgrade(invoice=True, licenses=100)

        with time_machine.travel(self.now, tick=False):
            result = self.client_patch("/json/billing/plan", {"licenses": 100})
            self.assert_json_error_contains(
                result, "Your plan is already on 100 licenses in the current billing period."
            )

        with time_machine.travel(self.now, tick=False):
            result = self.client_patch("/json/billing/plan", {"licenses_at_next_renewal": 100})
            self.assert_json_error_contains(
                result, "Your plan is already scheduled to renew with 100 licenses."
            )

        with time_machine.travel(self.now, tick=False):
            result = self.client_patch("/json/billing/plan", {"licenses": 50})
            self.assert_json_error_contains(
                result, "You cannot decrease the licenses in the current billing period."
            )

        with time_machine.travel(self.now, tick=False):
            result = self.client_patch("/json/billing/plan", {"licenses_at_next_renewal": 25})
            self.assert_json_error_contains(
                result,
                "You must purchase licenses for all active users in your organization (minimum 30).",
            )

        with time_machine.travel(self.now, tick=False):
            result = self.client_patch("/json/billing/plan", {"licenses": 2000})
            self.assert_json_error_contains(
                result, "Invoices with more than 1000 licenses can't be processed from this page."
            )

        with time_machine.travel(self.now, tick=False):
            result = self.client_patch("/json/billing/plan", {"licenses": 150})
            self.assert_json_success(result)
        invoice_plans_as_needed(self.next_year)
        stripe_customer = stripe_get_customer(
            assert_is_not_none(Customer.objects.get(realm=user.realm).stripe_customer_id)
        )
        [invoice, _] = iter(stripe.Invoice.list(customer=stripe_customer.id))
        invoice_params = {
            "amount_due": 8000 * 150 + 8000 * 50,
            "amount_paid": 0,
            "attempt_count": 0,
            "auto_advance": True,
            "collection_method": "send_invoice",
            "statement_descriptor": "Zulip Cloud Standard",
            "status": "open",
            "total": 8000 * 150 + 8000 * 50,
        }
        for key, value in invoice_params.items():
            self.assertEqual(invoice.get(key), value)
        [renewal_item, extra_license_item] = iter(invoice.lines)
        line_item_params = {
            "amount": 8000 * 150,
            "description": "Zulip Cloud Standard - renewal",
            "discountable": False,
            "period": {
                "end": datetime_to_timestamp(self.next_year + timedelta(days=365)),
                "start": datetime_to_timestamp(self.next_year),
            },
            "plan": None,
            "proration": False,
            "quantity": 150,
        }
        for key, value in line_item_params.items():
            self.assertEqual(renewal_item.get(key), value)
        line_item_params = {
            "amount": 8000 * 50,
            "description": "Additional license (Jan 2, 2012 - Jan 2, 2013)",
            "discountable": False,
            "period": {
                "end": datetime_to_timestamp(self.next_year),
                "start": datetime_to_timestamp(self.now),
            },
            "plan": None,
            "proration": False,
            "quantity": 50,
        }
        for key, value in line_item_params.items():
            self.assertEqual(extra_license_item.get(key), value)

        with time_machine.travel(self.next_year, tick=False):
            result = self.client_patch("/json/billing/plan", {"licenses_at_next_renewal": 120})
            self.assert_json_success(result)
        invoice_plans_as_needed(self.next_year + timedelta(days=365))
        stripe_customer = stripe_get_customer(
            assert_is_not_none(Customer.objects.get(realm=user.realm).stripe_customer_id)
        )
        [invoice, _, _] = iter(stripe.Invoice.list(customer=stripe_customer.id))
        invoice_params = {
            "amount_due": 8000 * 120,
            "amount_paid": 0,
            "attempt_count": 0,
            "auto_advance": True,
            "collection_method": "send_invoice",
            "statement_descriptor": "Zulip Cloud Standard",
            "status": "open",
            "total": 8000 * 120,
        }
        for key, value in invoice_params.items():
            self.assertEqual(invoice.get(key), value)
        [renewal_item] = iter(invoice.lines)
        line_item_params = {
            "amount": 8000 * 120,
            "description": "Zulip Cloud Standard - renewal",
            "discountable": False,
            "period": {
                "end": datetime_to_timestamp(self.next_year + timedelta(days=2 * 365)),
                "start": datetime_to_timestamp(self.next_year + timedelta(days=365)),
            },
            "plan": None,
            "proration": False,
            "quantity": 120,
        }
        for key, value in line_item_params.items():
            self.assertEqual(renewal_item.get(key), value)

    def test_update_licenses_of_manual_plan_from_billing_page_exempt_from_license_number_check(
        self,
    ) -> None:
        """
        Verifies that an organization exempt from the license number check can reduce their number
        of licenses.
        """
        user = self.example_user("hamlet")
        self.login_user(user)

        customer = Customer.objects.get_or_create(realm=user.realm)[0]
        customer.exempt_from_license_number_check = True
        customer.save()

        with time_machine.travel(self.now, tick=False):
            self.local_upgrade(100, False, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False)

        with time_machine.travel(self.now, tick=False):
            result = self.client_patch(
                "/json/billing/plan",
                {"licenses_at_next_renewal": get_latest_seat_count(user.realm) - 2},
            )

        self.assert_json_success(result)
        latest_license_ledger = LicenseLedger.objects.last()
        assert latest_license_ledger is not None
        self.assertEqual(
            latest_license_ledger.licenses_at_next_renewal, get_latest_seat_count(user.realm) - 2
        )

    def test_upgrade_exempt_from_license_number_check_realm_less_licenses_than_seat_count(
        self,
    ) -> None:
        """
        Verifies that an organization exempt from the license number check can upgrade their plan,
        specifying a number of licenses less than their current number of licenses and be charged
        for the number of licenses specified. Tests against a former bug, where the organization
        was charged for the current seat count, despite specifying a lower number of licenses.
        """
        user = self.example_user("hamlet")
        self.login_user(user)

        customer = Customer.objects.get_or_create(realm=user.realm)[0]
        customer.exempt_from_license_number_check = True
        customer.save()

        reduced_seat_count = get_latest_seat_count(user.realm) - 2

        with time_machine.travel(self.now, tick=False):
            self.local_upgrade(
                reduced_seat_count, False, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
            )

        latest_license_ledger = LicenseLedger.objects.last()
        assert latest_license_ledger is not None
        self.assertEqual(latest_license_ledger.licenses_at_next_renewal, reduced_seat_count)
        self.assertEqual(latest_license_ledger.licenses, reduced_seat_count)

    def test_update_licenses_of_automatic_plan_from_billing_page(self) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)

        with time_machine.travel(self.now, tick=False):
            self.local_upgrade(
                self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
            )

        with time_machine.travel(self.now, tick=False):
            result = self.client_patch("/json/billing/plan", {"licenses": 100})
            self.assert_json_error_contains(result, "Your plan is on automatic license management.")

        with time_machine.travel(self.now, tick=False):
            result = self.client_patch("/json/billing/plan", {"licenses_at_next_renewal": 100})
            self.assert_json_error_contains(result, "Your plan is on automatic license management.")

    def test_update_plan_with_invalid_status(self) -> None:
        with time_machine.travel(self.now, tick=False):
            self.local_upgrade(
                self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
            )
        self.login_user(self.example_user("hamlet"))

        response = self.client_patch(
            "/json/billing/plan",
            {"status": CustomerPlan.NEVER_STARTED},
        )
        self.assert_json_error_contains(response, "Invalid status")

    def test_update_plan_without_any_params(self) -> None:
        with time_machine.travel(self.now, tick=False):
            self.local_upgrade(
                self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
            )

        self.login_user(self.example_user("hamlet"))
        with time_machine.travel(self.now, tick=False):
            response = self.client_patch("/json/billing/plan", {})
        self.assert_json_error_contains(response, "Nothing to change")

    def test_update_plan_that_which_is_due_for_expiry(self) -> None:
        with time_machine.travel(self.now, tick=False):
            self.local_upgrade(
                self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
            )

        self.login_user(self.example_user("hamlet"))
        with self.assertLogs("corporate.stripe", "INFO") as m:
            with time_machine.travel(self.now, tick=False):
                result = self.client_patch(
                    "/json/billing/plan", {"status": CustomerPlan.DOWNGRADE_AT_END_OF_CYCLE}
                )
                self.assert_json_success(result)
                self.assertRegex(
                    m.output[0],
                    r"INFO:corporate.stripe:Change plan status: Customer.id: \d*, CustomerPlan.id: \d*, status: 2",
                )

        with time_machine.travel(self.next_year, tick=False):
            result = self.client_patch("/json/billing/plan", {"status": CustomerPlan.ACTIVE})
            self.assert_json_error_contains(
                result, "Unable to update the plan. The plan has ended."
            )

    def test_update_plan_that_which_is_due_for_replacement(self) -> None:
        with time_machine.travel(self.now, tick=False):
            self.local_upgrade(
                self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_MONTHLY, True, False
            )

        self.login_user(self.example_user("hamlet"))
        with self.assertLogs("corporate.stripe", "INFO") as m:
            with time_machine.travel(self.now, tick=False):
                result = self.client_patch(
                    "/json/billing/plan", {"status": CustomerPlan.SWITCH_TO_ANNUAL_AT_END_OF_CYCLE}
                )
                self.assert_json_success(result)
                self.assertRegex(
                    m.output[0],
                    r"INFO:corporate.stripe:Change plan status: Customer.id: \d*, CustomerPlan.id: \d*, status: 4",
                )

        with time_machine.travel(self.next_month, tick=False):
            result = self.client_patch("/json/billing/plan", {})
            self.assert_json_error_contains(
                result,
                "Unable to update the plan. The plan has been expired and replaced with a new plan.",
            )

    @patch("corporate.lib.stripe.billing_logger.info")
    def test_deactivate_realm(self, mock_: Mock) -> None:
        user = self.example_user("hamlet")
        with time_machine.travel(self.now, tick=False):
            self.local_upgrade(
                self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
            )

        plan = CustomerPlan.objects.get()
        self.assertEqual(plan.next_invoice_date, self.next_month)
        self.assertEqual(get_realm("zulip").plan_type, Realm.PLAN_TYPE_STANDARD)
        self.assertEqual(plan.status, CustomerPlan.ACTIVE)

        # Add some extra users before the realm is deactivated
        billing_session = RealmBillingSession(user=user, realm=user.realm)
        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=20):
            billing_session.update_license_ledger_if_needed(self.now)

        last_ledger_entry = LicenseLedger.objects.order_by("id").last()
        assert last_ledger_entry is not None
        self.assertEqual(last_ledger_entry.licenses, 20)
        self.assertEqual(last_ledger_entry.licenses_at_next_renewal, 20)

        do_deactivate_realm(get_realm("zulip"), acting_user=None)

        plan.refresh_from_db()
        self.assertTrue(get_realm("zulip").deactivated)
        self.assertEqual(get_realm("zulip").plan_type, Realm.PLAN_TYPE_LIMITED)
        self.assertEqual(plan.status, CustomerPlan.ENDED)
        self.assertEqual(plan.invoiced_through, last_ledger_entry)
        self.assertIsNone(plan.next_invoice_date)

        do_reactivate_realm(get_realm("zulip"))

        self.login_user(user)
        response = self.client_get("/billing/")
        self.assertEqual(response.status_code, 302)
        self.assertEqual("/plans/", response["Location"])

        # The extra users added in the final month are not charged
        with patch("corporate.lib.stripe.BillingSession.invoice_plan") as mocked:
            invoice_plans_as_needed(self.next_month)
        mocked.assert_not_called()

        # The plan is not renewed after an year
        with patch("corporate.lib.stripe.BillingSession.invoice_plan") as mocked:
            invoice_plans_as_needed(self.next_year)
        mocked.assert_not_called()

    def test_reupgrade_by_billing_admin_after_realm_deactivation(self) -> None:
        user = self.example_user("hamlet")

        with time_machine.travel(self.now, tick=False):
            self.local_upgrade(
                self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
            )

        do_deactivate_realm(get_realm("zulip"), acting_user=None)
        self.assertTrue(get_realm("zulip").deactivated)
        do_reactivate_realm(get_realm("zulip"))

        self.login_user(user)
        response = self.client_get("/billing/")
        self.assertEqual(response.status_code, 302)
        self.assertEqual("/plans/", response["Location"])

        with time_machine.travel(self.now, tick=False):
            self.local_upgrade(
                self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
            )

        self.assertEqual(Customer.objects.count(), 1)

        self.assertEqual(CustomerPlan.objects.count(), 2)

        current_plan = CustomerPlan.objects.all().order_by("id").last()
        assert current_plan is not None
        self.assertEqual(current_plan.next_invoice_date, self.next_month)
        self.assertEqual(get_realm("zulip").plan_type, Realm.PLAN_TYPE_STANDARD)
        self.assertEqual(current_plan.status, CustomerPlan.ACTIVE)

        old_plan = CustomerPlan.objects.all().order_by("id").first()
        assert old_plan is not None
        self.assertEqual(old_plan.next_invoice_date, None)
        self.assertEqual(old_plan.status, CustomerPlan.ENDED)

    @mock_stripe()
    def test_void_all_open_invoices(self, *mock: Mock) -> None:
        iago = self.example_user("iago")
        king = self.lear_user("king")

        voided_invoice_count = RealmBillingSession(
            user=None, realm=iago.realm
        ).void_all_open_invoices()
        self.assertEqual(voided_invoice_count, 0)

        zulip_customer = RealmBillingSession(iago).update_or_create_stripe_customer()
        lear_customer = RealmBillingSession(king).update_or_create_stripe_customer()

        assert zulip_customer.stripe_customer_id
        stripe.InvoiceItem.create(
            currency="usd",
            customer=zulip_customer.stripe_customer_id,
            description="Zulip Cloud Standard upgrade",
            discountable=False,
            unit_amount=800,
            quantity=8,
        )
        stripe_invoice = stripe.Invoice.create(
            auto_advance=True,
            collection_method="send_invoice",
            customer=zulip_customer.stripe_customer_id,
            days_until_due=30,
            statement_descriptor="Zulip Cloud Standard",
        )
        stripe.Invoice.finalize_invoice(stripe_invoice)

        assert lear_customer.stripe_customer_id
        stripe.InvoiceItem.create(
            currency="usd",
            customer=lear_customer.stripe_customer_id,
            description="Zulip Cloud Standard upgrade",
            discountable=False,
            unit_amount=800,
            quantity=8,
        )
        stripe_invoice = stripe.Invoice.create(
            auto_advance=True,
            collection_method="send_invoice",
            customer=lear_customer.stripe_customer_id,
            days_until_due=30,
            statement_descriptor="Zulip Cloud Standard",
        )
        stripe.Invoice.finalize_invoice(stripe_invoice)

        voided_invoice_count = RealmBillingSession(
            user=None, realm=iago.realm
        ).void_all_open_invoices()
        self.assertEqual(voided_invoice_count, 1)
        invoices = stripe.Invoice.list(customer=zulip_customer.stripe_customer_id)
        self.assert_length(invoices, 1)
        for invoice in invoices:
            self.assertEqual(invoice.status, "void")

        lear_stripe_customer_id = lear_customer.stripe_customer_id
        lear_customer.stripe_customer_id = None
        lear_customer.save(update_fields=["stripe_customer_id"])
        voided_invoice_count = RealmBillingSession(
            user=None, realm=king.realm
        ).void_all_open_invoices()
        self.assertEqual(voided_invoice_count, 0)

        lear_customer.stripe_customer_id = lear_stripe_customer_id
        lear_customer.save(update_fields=["stripe_customer_id"])
        voided_invoice_count = RealmBillingSession(
            user=None, realm=king.realm
        ).void_all_open_invoices()
        self.assertEqual(voided_invoice_count, 1)
        invoices = stripe.Invoice.list(customer=lear_customer.stripe_customer_id)
        self.assert_length(invoices, 1)
        for invoice in invoices:
            self.assertEqual(invoice.status, "void")

    def create_invoices(self, customer: Customer, num_invoices: int) -> List[stripe.Invoice]:
        invoices = []
        assert customer.stripe_customer_id is not None
        for _ in range(num_invoices):
            stripe.InvoiceItem.create(
                amount=10000,
                currency="usd",
                customer=customer.stripe_customer_id,
                description="Zulip Cloud Standard",
                discountable=False,
            )
            invoice = stripe.Invoice.create(
                auto_advance=True,
                collection_method="send_invoice",
                customer=customer.stripe_customer_id,
                days_until_due=DEFAULT_INVOICE_DAYS_UNTIL_DUE,
                statement_descriptor="Zulip Cloud Standard",
            )
            stripe.Invoice.finalize_invoice(invoice)
            invoices.append(invoice)
        return invoices

    @mock_stripe()
    def test_downgrade_small_realms_behind_on_payments_as_needed(self, *mock: Mock) -> None:
        test_realm_count = 0

        def create_realm(
            users_to_create: int,
            create_stripe_customer: bool,
            create_plan: bool,
            num_invoices: Optional[int] = None,
        ) -> Tuple[Realm, Optional[CustomerPlan], List[stripe.Invoice]]:
            nonlocal test_realm_count
            test_realm_count += 1
            realm_string_id = "test-realm-" + str(test_realm_count)
            realm = do_create_realm(
                string_id=realm_string_id,
                name=realm_string_id,
                plan_type=Realm.PLAN_TYPE_SELF_HOSTED,
            )
            users = []
            for i in range(users_to_create):
                user = UserProfile.objects.create(
                    delivery_email=f"user-{i}-{realm_string_id}@zulip.com",
                    email=f"user-{i}-{realm_string_id}@zulip.com",
                    realm=realm,
                )
                users.append(user)

            customer = None
            if create_stripe_customer:
                billing_session = RealmBillingSession(users[0])
                customer = billing_session.create_stripe_customer()
            plan = None
            if create_plan:
                plan, _ = self.subscribe_realm_to_monthly_plan_on_manual_license_management(
                    realm, users_to_create, users_to_create
                )
            invoices = []
            if num_invoices is not None:
                assert customer is not None
                invoices = self.create_invoices(customer, num_invoices)
            return realm, plan, invoices

        @dataclass
        class Row:
            realm: Realm
            expected_plan_type: int
            plan: Optional[CustomerPlan]
            expected_plan_status: Optional[int]
            expected_invoice_count: int
            email_expected_to_be_sent: bool

        rows: List[Row] = []

        # no stripe customer ID (excluded from query)
        realm, _, _ = create_realm(
            users_to_create=1, create_stripe_customer=False, create_plan=False
        )
        billing_session = RealmBillingSession(
            user=self.example_user("iago"), realm=realm, support_session=True
        )
        billing_session.attach_discount_to_customer(Decimal(20))
        rows.append(Row(realm, Realm.PLAN_TYPE_SELF_HOSTED, None, None, 0, False))

        # no active paid plan or invoices (no action)
        realm, _, _ = create_realm(
            users_to_create=1, create_stripe_customer=True, create_plan=False
        )
        rows.append(Row(realm, Realm.PLAN_TYPE_SELF_HOSTED, None, None, 0, False))

        # no active plan, one unpaid invoice (will be voided, no downgrade or email)
        realm, _, _ = create_realm(
            users_to_create=1, create_stripe_customer=True, create_plan=False, num_invoices=1
        )
        rows.append(Row(realm, Realm.PLAN_TYPE_SELF_HOSTED, None, None, 0, False))

        # active plan, no invoices (no action)
        realm, plan, _ = create_realm(
            users_to_create=1, create_stripe_customer=True, create_plan=True
        )
        rows.append(Row(realm, Realm.PLAN_TYPE_STANDARD, plan, CustomerPlan.ACTIVE, 0, False))

        # active plan, only one unpaid invoice (not downgraded or voided)
        realm, plan, _ = create_realm(
            users_to_create=1, create_stripe_customer=True, create_plan=True, num_invoices=1
        )
        rows.append(Row(realm, Realm.PLAN_TYPE_STANDARD, plan, CustomerPlan.ACTIVE, 1, False))

        # active plan, two unpaid invoices (will be downgraded, voided and emailed)
        realm, plan, _ = create_realm(
            users_to_create=3, create_stripe_customer=True, create_plan=True, num_invoices=2
        )
        rows.append(Row(realm, Realm.PLAN_TYPE_LIMITED, plan, CustomerPlan.ENDED, 0, True))

        # active plan, two paid invoices (not downgraded)
        realm, plan, invoices = create_realm(
            users_to_create=1, create_stripe_customer=True, create_plan=True, num_invoices=2
        )
        for invoice in invoices:
            stripe.Invoice.pay(invoice, paid_out_of_band=True)
        rows.append(Row(realm, Realm.PLAN_TYPE_STANDARD, plan, CustomerPlan.ACTIVE, 0, False))

        # not a small realm, two unpaid invoices (not downgraded or voided)
        realm, plan, _ = create_realm(
            users_to_create=20, create_stripe_customer=True, create_plan=True, num_invoices=2
        )
        rows.append(Row(realm, Realm.PLAN_TYPE_STANDARD, plan, CustomerPlan.ACTIVE, 2, False))

        # Customer objects without a realm should be excluded from query.
        remote_server = RemoteZulipServer.objects.create(
            uuid=str(uuid.uuid4()),
            api_key="magic_secret_api_key",
            hostname="demo.example.com",
            contact_email="email@example.com",
        )
        Customer.objects.create(remote_server=remote_server, stripe_customer_id="cus_xxx")

        downgrade_small_realms_behind_on_payments_as_needed()

        from django.core.mail import outbox

        for row in rows:
            row.realm.refresh_from_db()
            self.assertEqual(row.realm.plan_type, row.expected_plan_type)
            if row.plan is not None:
                row.plan.refresh_from_db()
                self.assertEqual(row.plan.status, row.expected_plan_status)
                customer = get_customer_by_realm(row.realm)
                if customer is not None and customer.stripe_customer_id is not None:
                    open_invoices = customer_has_last_n_invoices_open(
                        customer, row.expected_invoice_count
                    )
                    self.assertTrue(open_invoices)

            email_found = False
            for email in outbox:
                recipient = UserProfile.objects.get(email=email.to[0])
                if recipient.realm == row.realm:
                    self.assertIn(
                        f"Your organization, http://{row.realm.string_id}.testserver, has been downgraded",
                        outbox[0].body,
                    )
                    self.assert_length(email.to, 1)
                    self.assertTrue(recipient.is_billing_admin)
                    email_found = True
            self.assertEqual(row.email_expected_to_be_sent, email_found)

    @mock_stripe()
    def test_change_plan_tier_from_standard_to_plus(self, *mock: Mock) -> None:
        iago = self.example_user("iago")
        realm = iago.realm
        iago_billing_session = RealmBillingSession(iago)
        iago_billing_session.update_or_create_customer()

        # Test upgrading to Plus when realm has no active subscription
        with self.assertRaises(BillingError) as billing_context:
            iago_billing_session.do_change_plan_to_new_tier(CustomerPlan.TIER_CLOUD_PLUS)
        self.assertEqual(
            "Organization does not have an active plan",
            billing_context.exception.error_description,
        )

        plan, ledger = self.subscribe_realm_to_manual_license_management_plan(
            realm, 9, 9, CustomerPlan.BILLING_SCHEDULE_MONTHLY
        )
        # Test upgrading to Plus when realm has no stripe_customer_id
        with self.assertRaises(BillingError) as billing_context:
            iago_billing_session.do_change_plan_to_new_tier(CustomerPlan.TIER_CLOUD_PLUS)
        self.assertEqual(
            "Organization missing Stripe customer.", billing_context.exception.error_description
        )

        king = self.lear_user("king")
        realm = king.realm
        king_billing_session = RealmBillingSession(king)
        customer = king_billing_session.update_or_create_stripe_customer()
        plan = CustomerPlan.objects.create(
            customer=customer,
            automanage_licenses=True,
            billing_cycle_anchor=timezone_now(),
            billing_schedule=CustomerPlan.BILLING_SCHEDULE_MONTHLY,
            tier=CustomerPlan.TIER_CLOUD_STANDARD,
        )
        ledger = LicenseLedger.objects.create(
            plan=plan,
            is_renewal=True,
            event_time=timezone_now(),
            licenses=9,
            licenses_at_next_renewal=9,
        )
        realm.plan_type = Realm.PLAN_TYPE_STANDARD
        realm.save(update_fields=["plan_type"])
        plan.invoiced_through = ledger
        plan.price_per_license = get_price_per_license(
            CustomerPlan.TIER_CLOUD_STANDARD, CustomerPlan.BILLING_SCHEDULE_MONTHLY
        )
        plan.save(update_fields=["invoiced_through", "price_per_license"])

        with self.assertRaises(BillingError) as billing_context:
            king_billing_session.do_change_plan_to_new_tier(CustomerPlan.TIER_CLOUD_STANDARD)
        self.assertEqual(
            "Invalid change of customer plan tier.", billing_context.exception.error_description
        )

        king_billing_session.do_change_plan_to_new_tier(CustomerPlan.TIER_CLOUD_PLUS)

        plan.refresh_from_db()
        self.assertEqual(plan.status, CustomerPlan.ENDED)
        plus_plan = get_current_plan_by_realm(realm)
        assert plus_plan is not None
        self.assertEqual(plus_plan.tier, CustomerPlan.TIER_CLOUD_PLUS)
        self.assertEqual(LicenseLedger.objects.filter(plan=plus_plan).count(), 1)

        realm.refresh_from_db()
        self.assertEqual(realm.plan_type, Realm.PLAN_TYPE_PLUS)

        # There are 9 licenses and the realm is on the Standard monthly plan.
        # Therefore, the customer has already paid 800 * 9 = 7200 = $72 for
        # the month. Once they upgrade to Plus, the new price for their 9
        # licenses will be 1600 * 9 = 14400 = $144. Since the customer has
        # already paid $72 for a month, -7200 = -$72 will be credited to the
        # customer's balance.
        stripe_customer_id = customer.stripe_customer_id
        assert stripe_customer_id is not None
        _, cb_txn = iter(stripe.Customer.list_balance_transactions(stripe_customer_id))
        self.assertEqual(cb_txn.amount, -7200)
        self.assertEqual(
            cb_txn.description,
            "Credit from early termination of active plan",
        )
        self.assertEqual(cb_txn.type, "adjustment")

        # The customer now only pays the difference 14400 - 7200 = 7200 = $72,
        # since the unused proration is for the whole month.
        (invoice,) = iter(stripe.Invoice.list(customer=stripe_customer_id))
        self.assertEqual(invoice.amount_due, 7200)

    @mock_stripe()
    def test_customer_has_credit_card_as_default_payment_method(self, *mocks: Mock) -> None:
        iago = self.example_user("iago")
        customer = Customer.objects.create(realm=iago.realm)
        self.assertFalse(customer_has_credit_card_as_default_payment_method(customer))

        billing_session = RealmBillingSession(iago)
        customer = billing_session.update_or_create_stripe_customer()
        self.assertFalse(customer_has_credit_card_as_default_payment_method(customer))

        self.login_user(iago)
        self.add_card_and_upgrade(iago)
        self.assertTrue(customer_has_credit_card_as_default_payment_method(customer))


class StripeWebhookEndpointTest(ZulipTestCase):
    def test_stripe_webhook_with_invalid_data(self) -> None:
        result = self.client_post(
            "/stripe/webhook/",
            '["dsdsds"]',
            content_type="application/json",
        )
        self.assertEqual(result.status_code, 400)

    def test_stripe_webhook_endpoint_invalid_api_version(self) -> None:
        event_data = {
            "id": "stripe_event_id",
            "api_version": "1991-02-20",
            "type": "event_type",
            "data": {"object": {"object": "checkout.session", "id": "stripe_session_id"}},
        }

        expected_error_message = rf"Mismatch between billing system Stripe API version({STRIPE_API_VERSION}) and Stripe webhook event API version(1991-02-20)."
        with self.assertLogs("corporate.stripe", "ERROR") as error_log:
            self.client_post(
                "/stripe/webhook/",
                event_data,
                content_type="application/json",
            )
            self.assertEqual(error_log.output, [f"ERROR:corporate.stripe:{expected_error_message}"])

    def test_stripe_webhook_for_session_completed_event(self) -> None:
        # We don't process sessions for which we don't have a `Session` entry.
        valid_session_event_data = {
            "id": "stripe_event_id",
            "api_version": STRIPE_API_VERSION,
            "type": "checkout.session.completed",
            "data": {"object": {"object": "checkout.session", "id": "stripe_session_id"}},
        }
        with patch("corporate.views.webhook.handle_checkout_session_completed_event") as m:
            result = self.client_post(
                "/stripe/webhook/",
                valid_session_event_data,
                content_type="application/json",
            )
        self.assert_length(Event.objects.all(), 0)
        self.assertEqual(result.status_code, 200)
        m.assert_not_called()

    def test_stripe_webhook_for_payment_intent_events(self) -> None:
        customer = Customer.objects.create(realm=get_realm("zulip"))

        stripe_event_id = "stripe_event_id"
        stripe_payment_intent_id = "stripe_payment_intent_id"
        valid_session_event_data = {
            "id": stripe_event_id,
            "type": "payment_intent.succeeded",
            "api_version": STRIPE_API_VERSION,
            "data": {"object": {"object": "payment_intent", "id": stripe_payment_intent_id}},
        }

        with patch("corporate.views.webhook.handle_payment_intent_succeeded_event") as m:
            result = self.client_post(
                "/stripe/webhook/",
                valid_session_event_data,
                content_type="application/json",
            )
        self.assert_length(Event.objects.filter(stripe_event_id=stripe_event_id), 0)
        self.assertEqual(result.status_code, 200)
        m.assert_not_called()

        PaymentIntent.objects.create(
            stripe_payment_intent_id=stripe_payment_intent_id,
            customer=customer,
            status=PaymentIntent.REQUIRES_PAYMENT_METHOD,
        )

        self.assert_length(Event.objects.filter(stripe_event_id=stripe_event_id), 0)
        with patch("corporate.views.webhook.handle_payment_intent_succeeded_event") as m:
            result = self.client_post(
                "/stripe/webhook/",
                valid_session_event_data,
                content_type="application/json",
            )
        [event] = Event.objects.filter(stripe_event_id=stripe_event_id)
        self.assertEqual(result.status_code, 200)
        strip_event = stripe.Event.construct_from(valid_session_event_data, stripe.api_key)
        m.assert_called_once_with(strip_event.data.object, event)

        with patch("corporate.views.webhook.handle_payment_intent_succeeded_event") as m:
            result = self.client_post(
                "/stripe/webhook/",
                valid_session_event_data,
                content_type="application/json",
            )
        self.assert_length(Event.objects.filter(stripe_event_id=stripe_event_id), 1)
        self.assertEqual(result.status_code, 200)
        m.assert_not_called()


class EventStatusTest(StripeTestCase):
    def test_event_status_json_endpoint_errors(self) -> None:
        self.login_user(self.example_user("iago"))

        response = self.client_get("/json/billing/event/status")
        self.assert_json_error_contains(response, "No customer for this organization!")

        Customer.objects.create(realm=get_realm("zulip"), stripe_customer_id="cus_123")
        response = self.client_get(
            "/json/billing/event/status", {"stripe_session_id": "invalid_session_id"}
        )
        self.assert_json_error_contains(response, "Session not found")

        response = self.client_get(
            "/json/billing/event/status", {"stripe_payment_intent_id": "invalid_payment_intent_id"}
        )
        self.assert_json_error_contains(response, "Payment intent not found")

        response = self.client_get(
            "/json/billing/event/status",
        )
        self.assert_json_error_contains(
            response, "Pass stripe_session_id or stripe_payment_intent_id"
        )

    def test_event_status_page(self) -> None:
        self.login_user(self.example_user("polonius"))

        stripe_session_id = "cs_test_9QCz62mPTJQUwvhcwZHBpJMHmMZiLU512AQHU9g5znkx6NweU3j7kJvY"
        response = self.client_get(
            "/billing/event_status/", {"stripe_session_id": stripe_session_id}
        )
        self.assert_in_success_response([f'data-stripe-session-id="{stripe_session_id}"'], response)

        stripe_payment_intent_id = "pi_1JGLpnA4KHR4JzRvUfkF9Tn7"
        response = self.client_get(
            "/billing/event_status/", {"stripe_payment_intent_id": stripe_payment_intent_id}
        )
        self.assert_in_success_response(
            [f'data-stripe-payment-intent-id="{stripe_payment_intent_id}"'], response
        )


class RequiresBillingAccessTest(StripeTestCase):
    @override
    def setUp(self, *mocks: Mock) -> None:
        super().setUp()
        desdemona = self.example_user("desdemona")
        desdemona.role = UserProfile.ROLE_REALM_OWNER
        desdemona.save(update_fields=["role"])

    def test_json_endpoints_permissions(self) -> None:
        guest = self.example_user("polonius")
        member = self.example_user("othello")
        realm_admin = self.example_user("iago")

        billing_admin = self.example_user("hamlet")
        billing_admin.is_billing_admin = True
        billing_admin.save(update_fields=["is_billing_admin"])

        tested_endpoints = set()

        def check_users_cant_access(
            users: List[UserProfile],
            error_message: str,
            url: str,
            method: str,
            data: Dict[str, Any],
        ) -> None:
            tested_endpoints.add(url)
            for user in users:
                self.login_user(user)
                if method == "POST":
                    client_func: Any = self.client_post
                elif method == "GET":
                    client_func = self.client_get
                else:
                    client_func = self.client_patch
                result = client_func(
                    url,
                    data,
                    content_type="application/json",
                )
                self.assert_json_error_contains(result, error_message)

        check_users_cant_access(
            [guest],
            "Must be an organization member",
            "/json/billing/upgrade",
            "POST",
            {},
        )

        check_users_cant_access(
            [guest],
            "Must be an organization member",
            "/json/billing/sponsorship",
            "POST",
            {},
        )

        check_users_cant_access(
            [guest, member, realm_admin],
            "Must be a billing administrator or an organization owner",
            "/json/billing/plan",
            "PATCH",
            {},
        )

        check_users_cant_access(
            [guest, member, realm_admin],
            "Must be a billing administrator or an organization owner",
            "/json/billing/session/start_card_update_session",
            "POST",
            {},
        )

        check_users_cant_access(
            [guest],
            "Must be an organization member",
            "/json/upgrade/session/start_card_update_session",
            "POST",
            {},
        )

        check_users_cant_access(
            [guest],
            "Must be an organization member",
            "/json/billing/event/status",
            "GET",
            {},
        )

        # Make sure that we are testing all the JSON endpoints
        # Quite a hack, but probably fine for now
        reverse_dict = get_resolver("corporate.urls").reverse_dict
        json_endpoints = {
            pat
            for name in reverse_dict
            for matches, pat, defaults, converters in reverse_dict.getlist(name)
            if pat.startswith("json/") and not (pat.startswith(("json/realm/", "json/server/")))
        }
        self.assert_length(json_endpoints, len(tested_endpoints))

    @mock_stripe()
    def test_billing_page_permissions(self, *mocks: Mock) -> None:
        # Guest users can't access /upgrade/ page
        self.login_user(self.example_user("polonius"))
        response = self.client_get("/upgrade/", follow=True)
        self.assertEqual(response.status_code, 404)

        non_owner_non_billing_admin = self.example_user("othello")
        self.login_user(non_owner_non_billing_admin)
        response = self.client_get("/billing/")
        self.assert_in_success_response(
            ["You must be an organization owner or a billing administrator to view this page."],
            response,
        )
        # Check that non-admins can sign up and pay
        self.add_card_and_upgrade(non_owner_non_billing_admin)
        # Check that the non-admin othello can still access /billing
        response = self.client_get("/billing/")
        self.assert_in_success_response(["Zulip Cloud Standard"], response)
        self.assert_not_in_success_response(
            ["You must be an organization owner or a billing administrator to view this page."],
            response,
        )

        # Check realm owners can access billing, even though they are not a billing admin
        desdemona = self.example_user("desdemona")
        desdemona.role = UserProfile.ROLE_REALM_OWNER
        desdemona.save(update_fields=["role"])
        self.login_user(self.example_user("desdemona"))
        response = self.client_get("/billing/")
        self.assert_in_success_response(["Zulip Cloud Standard"], response)

        # Check that member who is not a billing admin does not have access
        self.login_user(self.example_user("cordelia"))
        response = self.client_get("/billing/")
        self.assert_in_success_response(
            ["You must be an organization owner or a billing administrator"], response
        )


class BillingHelpersTest(ZulipTestCase):
    def test_next_month(self) -> None:
        anchor = datetime(2019, 12, 31, 1, 2, 3, tzinfo=timezone.utc)
        period_boundaries = [
            anchor,
            datetime(2020, 1, 31, 1, 2, 3, tzinfo=timezone.utc),
            # Test that this is the 28th even during leap years
            datetime(2020, 2, 28, 1, 2, 3, tzinfo=timezone.utc),
            datetime(2020, 3, 31, 1, 2, 3, tzinfo=timezone.utc),
            datetime(2020, 4, 30, 1, 2, 3, tzinfo=timezone.utc),
            datetime(2020, 5, 31, 1, 2, 3, tzinfo=timezone.utc),
            datetime(2020, 6, 30, 1, 2, 3, tzinfo=timezone.utc),
            datetime(2020, 7, 31, 1, 2, 3, tzinfo=timezone.utc),
            datetime(2020, 8, 31, 1, 2, 3, tzinfo=timezone.utc),
            datetime(2020, 9, 30, 1, 2, 3, tzinfo=timezone.utc),
            datetime(2020, 10, 31, 1, 2, 3, tzinfo=timezone.utc),
            datetime(2020, 11, 30, 1, 2, 3, tzinfo=timezone.utc),
            datetime(2020, 12, 31, 1, 2, 3, tzinfo=timezone.utc),
            datetime(2021, 1, 31, 1, 2, 3, tzinfo=timezone.utc),
            datetime(2021, 2, 28, 1, 2, 3, tzinfo=timezone.utc),
        ]
        with self.assertRaises(AssertionError):
            add_months(anchor, -1)
        # Explicitly test add_months for each value of MAX_DAY_FOR_MONTH and
        # for crossing a year boundary
        for i, boundary in enumerate(period_boundaries):
            self.assertEqual(add_months(anchor, i), boundary)
        # Test next_month for small values
        for last, next_ in zip(period_boundaries[:-1], period_boundaries[1:]):
            self.assertEqual(next_month(anchor, last), next_)
        # Test next_month for large values
        period_boundaries = [dt.replace(year=dt.year + 100) for dt in period_boundaries]
        for last, next_ in zip(period_boundaries[:-1], period_boundaries[1:]):
            self.assertEqual(next_month(anchor, last), next_)

    def test_compute_plan_parameters(self) -> None:
        # TODO: test rounding down microseconds
        anchor = datetime(2019, 12, 31, 1, 2, 3, tzinfo=timezone.utc)
        month_later = datetime(2020, 1, 31, 1, 2, 3, tzinfo=timezone.utc)
        year_later = datetime(2020, 12, 31, 1, 2, 3, tzinfo=timezone.utc)
        test_cases = [
            # test all possibilities, since there aren't that many
            (
                (
                    CustomerPlan.TIER_CLOUD_STANDARD,
                    True,
                    CustomerPlan.BILLING_SCHEDULE_ANNUAL,
                    None,
                ),
                (anchor, month_later, year_later, 8000),
            ),
            (
                (CustomerPlan.TIER_CLOUD_STANDARD, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, 85),
                (anchor, month_later, year_later, 1200),
            ),
            (
                (
                    CustomerPlan.TIER_CLOUD_STANDARD,
                    True,
                    CustomerPlan.BILLING_SCHEDULE_MONTHLY,
                    None,
                ),
                (anchor, month_later, month_later, 800),
            ),
            (
                (CustomerPlan.TIER_CLOUD_STANDARD, True, CustomerPlan.BILLING_SCHEDULE_MONTHLY, 85),
                (anchor, month_later, month_later, 120),
            ),
            (
                (
                    CustomerPlan.TIER_CLOUD_STANDARD,
                    False,
                    CustomerPlan.BILLING_SCHEDULE_ANNUAL,
                    None,
                ),
                (anchor, year_later, year_later, 8000),
            ),
            (
                (CustomerPlan.TIER_CLOUD_STANDARD, False, CustomerPlan.BILLING_SCHEDULE_ANNUAL, 85),
                (anchor, year_later, year_later, 1200),
            ),
            (
                (
                    CustomerPlan.TIER_CLOUD_STANDARD,
                    False,
                    CustomerPlan.BILLING_SCHEDULE_MONTHLY,
                    None,
                ),
                (anchor, month_later, month_later, 800),
            ),
            (
                (
                    CustomerPlan.TIER_CLOUD_STANDARD,
                    False,
                    CustomerPlan.BILLING_SCHEDULE_MONTHLY,
                    85,
                ),
                (anchor, month_later, month_later, 120),
            ),
            # test exact math of Decimals; 800 * (1 - 87.25) = 101.9999999..
            (
                (
                    CustomerPlan.TIER_CLOUD_STANDARD,
                    False,
                    CustomerPlan.BILLING_SCHEDULE_MONTHLY,
                    87.25,
                ),
                (anchor, month_later, month_later, 102),
            ),
            # test dropping of fractional cents; without the int it's 102.8
            (
                (
                    CustomerPlan.TIER_CLOUD_STANDARD,
                    False,
                    CustomerPlan.BILLING_SCHEDULE_MONTHLY,
                    87.15,
                ),
                (anchor, month_later, month_later, 102),
            ),
        ]
        with time_machine.travel(anchor, tick=False):
            for (tier, automanage_licenses, billing_schedule, discount), output in test_cases:
                output_ = compute_plan_parameters(
                    tier,
                    automanage_licenses,
                    billing_schedule,
                    None if discount is None else Decimal(discount),
                )
                self.assertEqual(output_, output)

    def test_get_price_per_license(self) -> None:
        self.assertEqual(
            get_price_per_license(
                CustomerPlan.TIER_CLOUD_STANDARD, CustomerPlan.BILLING_SCHEDULE_ANNUAL
            ),
            8000,
        )
        self.assertEqual(
            get_price_per_license(
                CustomerPlan.TIER_CLOUD_STANDARD, CustomerPlan.BILLING_SCHEDULE_MONTHLY
            ),
            800,
        )
        self.assertEqual(
            get_price_per_license(
                CustomerPlan.TIER_CLOUD_STANDARD,
                CustomerPlan.BILLING_SCHEDULE_MONTHLY,
                discount=Decimal(50),
            ),
            400,
        )

        self.assertEqual(
            get_price_per_license(
                CustomerPlan.TIER_CLOUD_PLUS, CustomerPlan.BILLING_SCHEDULE_ANNUAL
            ),
            16000,
        )
        self.assertEqual(
            get_price_per_license(
                CustomerPlan.TIER_CLOUD_PLUS, CustomerPlan.BILLING_SCHEDULE_MONTHLY
            ),
            1600,
        )
        self.assertEqual(
            get_price_per_license(
                CustomerPlan.TIER_CLOUD_PLUS,
                CustomerPlan.BILLING_SCHEDULE_MONTHLY,
                discount=Decimal(50),
            ),
            800,
        )

        with self.assertRaisesRegex(InvalidBillingScheduleError, "Unknown billing_schedule: 1000"):
            get_price_per_license(CustomerPlan.TIER_CLOUD_STANDARD, 1000)

        with self.assertRaisesRegex(InvalidTierError, "Unknown tier: 4"):
            get_price_per_license(
                CustomerPlan.TIER_CLOUD_ENTERPRISE, CustomerPlan.BILLING_SCHEDULE_ANNUAL
            )

    def test_get_plan_renewal_or_end_date(self) -> None:
        realm = get_realm("zulip")
        customer = Customer.objects.create(realm=realm, stripe_customer_id="cus_12345")
        billing_cycle_anchor = timezone_now()
        plan = CustomerPlan.objects.create(
            customer=customer,
            status=CustomerPlan.ACTIVE,
            billing_cycle_anchor=billing_cycle_anchor,
            billing_schedule=CustomerPlan.BILLING_SCHEDULE_MONTHLY,
            tier=CustomerPlan.TIER_CLOUD_STANDARD,
        )
        renewal_date = get_plan_renewal_or_end_date(plan, billing_cycle_anchor)
        self.assertEqual(renewal_date, add_months(billing_cycle_anchor, 1))

        # When the plan ends 2 days before the start of the next billing cycle,
        # the function should return the end_date.
        plan_end_date = add_months(billing_cycle_anchor, 1) - timedelta(days=2)
        plan.end_date = plan_end_date
        plan.save(update_fields=["end_date"])
        renewal_date = get_plan_renewal_or_end_date(plan, billing_cycle_anchor)
        self.assertEqual(renewal_date, plan_end_date)

    def test_update_or_create_stripe_customer_logic(self) -> None:
        user = self.example_user("hamlet")
        # No existing Customer object
        with patch(
            "corporate.lib.stripe.BillingSession.create_stripe_customer", return_value="returned"
        ) as mocked1:
            billing_session = RealmBillingSession(user)
            returned = billing_session.update_or_create_stripe_customer()
        mocked1.assert_called_once()
        self.assertEqual(returned, "returned")

        customer = Customer.objects.create(realm=get_realm("zulip"))
        # Customer exists but stripe_customer_id is None
        with patch(
            "corporate.lib.stripe.BillingSession.create_stripe_customer", return_value="returned"
        ) as mocked2:
            billing_session = RealmBillingSession(user)
            returned = billing_session.update_or_create_stripe_customer()
        mocked2.assert_called_once()
        self.assertEqual(returned, "returned")

        customer.stripe_customer_id = "cus_12345"
        customer.save()
        # Customer exists, replace payment source
        with patch("corporate.lib.stripe.BillingSession.replace_payment_method") as mocked3:
            billing_session = RealmBillingSession(user)
            returned_customer = billing_session.update_or_create_stripe_customer("pm_card_visa")
        mocked3.assert_called_once()
        self.assertEqual(returned_customer, customer)

        # Customer exists, do nothing
        with patch("corporate.lib.stripe.BillingSession.replace_payment_method") as mocked4:
            billing_session = RealmBillingSession(user)
            returned_customer = billing_session.update_or_create_stripe_customer(None)
        mocked4.assert_not_called()
        self.assertEqual(returned_customer, customer)

    def test_get_customer_by_realm(self) -> None:
        realm = get_realm("zulip")

        self.assertEqual(get_customer_by_realm(realm), None)

        customer = Customer.objects.create(realm=realm, stripe_customer_id="cus_12345")
        self.assertEqual(get_customer_by_realm(realm), customer)

    def test_get_current_plan_by_customer(self) -> None:
        realm = get_realm("zulip")
        customer = Customer.objects.create(realm=realm, stripe_customer_id="cus_12345")

        self.assertEqual(get_current_plan_by_customer(customer), None)

        plan = CustomerPlan.objects.create(
            customer=customer,
            status=CustomerPlan.ACTIVE,
            billing_cycle_anchor=timezone_now(),
            billing_schedule=CustomerPlan.BILLING_SCHEDULE_ANNUAL,
            tier=CustomerPlan.TIER_CLOUD_STANDARD,
        )
        self.assertEqual(get_current_plan_by_customer(customer), plan)

        plan.status = CustomerPlan.DOWNGRADE_AT_END_OF_CYCLE
        plan.save(update_fields=["status"])
        self.assertEqual(get_current_plan_by_customer(customer), plan)

        plan.status = CustomerPlan.ENDED
        plan.save(update_fields=["status"])
        self.assertEqual(get_current_plan_by_customer(customer), None)

        plan.status = CustomerPlan.NEVER_STARTED
        plan.save(update_fields=["status"])
        self.assertEqual(get_current_plan_by_customer(customer), None)

    def test_get_current_plan_by_realm(self) -> None:
        realm = get_realm("zulip")

        self.assertEqual(get_current_plan_by_realm(realm), None)

        customer = Customer.objects.create(realm=realm, stripe_customer_id="cus_12345")
        self.assertEqual(get_current_plan_by_realm(realm), None)

        plan = CustomerPlan.objects.create(
            customer=customer,
            status=CustomerPlan.ACTIVE,
            billing_cycle_anchor=timezone_now(),
            billing_schedule=CustomerPlan.BILLING_SCHEDULE_ANNUAL,
            tier=CustomerPlan.TIER_CLOUD_STANDARD,
        )
        self.assertEqual(get_current_plan_by_realm(realm), plan)

    def test_is_realm_on_free_trial(self) -> None:
        realm = get_realm("zulip")
        self.assertFalse(is_realm_on_free_trial(realm))

        customer = Customer.objects.create(realm=realm, stripe_customer_id="cus_12345")
        plan = CustomerPlan.objects.create(
            customer=customer,
            status=CustomerPlan.ACTIVE,
            billing_cycle_anchor=timezone_now(),
            billing_schedule=CustomerPlan.BILLING_SCHEDULE_ANNUAL,
            tier=CustomerPlan.TIER_CLOUD_STANDARD,
        )
        self.assertFalse(is_realm_on_free_trial(realm))

        plan.status = CustomerPlan.FREE_TRIAL
        plan.save(update_fields=["status"])
        self.assertTrue(is_realm_on_free_trial(realm))

    def test_change_remote_server_plan_type(self) -> None:
        server_uuid = str(uuid.uuid4())
        remote_server = RemoteZulipServer.objects.create(
            uuid=server_uuid,
            api_key="magic_secret_api_key",
            hostname="demo.example.com",
            contact_email="email@example.com",
        )
        self.assertEqual(remote_server.plan_type, RemoteZulipServer.PLAN_TYPE_SELF_HOSTED)

        do_change_remote_server_plan_type(remote_server, RemoteZulipServer.PLAN_TYPE_BUSINESS)

        remote_server = RemoteZulipServer.objects.get(uuid=server_uuid)
        remote_realm_audit_log = RemoteZulipServerAuditLog.objects.filter(
            event_type=RealmAuditLog.REMOTE_SERVER_PLAN_TYPE_CHANGED
        ).last()
        assert remote_realm_audit_log is not None
        expected_extra_data = {
            "old_value": RemoteZulipServer.PLAN_TYPE_SELF_HOSTED,
            "new_value": RemoteZulipServer.PLAN_TYPE_BUSINESS,
        }
        self.assertEqual(remote_realm_audit_log.extra_data, expected_extra_data)
        self.assertEqual(remote_server.plan_type, RemoteZulipServer.PLAN_TYPE_BUSINESS)

    def test_deactivate_remote_server(self) -> None:
        server_uuid = str(uuid.uuid4())
        remote_server = RemoteZulipServer.objects.create(
            uuid=server_uuid,
            api_key="magic_secret_api_key",
            hostname="demo.example.com",
            contact_email="email@example.com",
        )
        self.assertFalse(remote_server.deactivated)

        do_deactivate_remote_server(remote_server)

        remote_server = RemoteZulipServer.objects.get(uuid=server_uuid)
        remote_realm_audit_log = RemoteZulipServerAuditLog.objects.filter(
            event_type=RealmAuditLog.REMOTE_SERVER_DEACTIVATED
        ).last()
        assert remote_realm_audit_log is not None
        self.assertTrue(remote_server.deactivated)

        # Try to deactivate a remote server that is already deactivated
        with self.assertLogs("corporate.stripe", "WARN") as warning_log:
            do_deactivate_remote_server(remote_server)
            self.assertEqual(
                warning_log.output,
                [
                    "WARNING:corporate.stripe:Cannot deactivate remote server with ID "
                    f"{remote_server.id}, server has already been deactivated."
                ],
            )


class AnalyticsHelpersTest(ZulipTestCase):
    def test_get_realms_to_default_discount_dict(self) -> None:
        Customer.objects.create(realm=get_realm("zulip"), stripe_customer_id="cus_1")
        lear_customer = Customer.objects.create(realm=get_realm("lear"), stripe_customer_id="cus_2")
        lear_customer.default_discount = Decimal(30)
        lear_customer.save(update_fields=["default_discount"])
        zephyr_customer = Customer.objects.create(
            realm=get_realm("zephyr"), stripe_customer_id="cus_3"
        )
        zephyr_customer.default_discount = Decimal(0)
        zephyr_customer.save(update_fields=["default_discount"])
        remote_server = RemoteZulipServer.objects.create(
            uuid=str(uuid.uuid4()),
            api_key="magic_secret_api_key",
            hostname="demo.example.com",
            contact_email="email@example.com",
        )
        remote_customer = Customer.objects.create(
            remote_server=remote_server, stripe_customer_id="cus_4"
        )
        remote_customer.default_discount = Decimal(50)
        remote_customer.save(update_fields=["default_discount"])

        self.assertEqual(
            get_realms_with_default_discount_dict(),
            {
                "lear": Decimal("30.0000"),
            },
        )


class LicenseLedgerTest(StripeTestCase):
    def test_add_plan_renewal_if_needed(self) -> None:
        with time_machine.travel(self.now, tick=False):
            self.local_upgrade(
                self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
            )
        self.assertEqual(LicenseLedger.objects.count(), 1)
        plan = CustomerPlan.objects.get()
        # Plan hasn't renewed yet
        realm = plan.customer.realm
        billing_session = RealmBillingSession(user=None, realm=realm)
        billing_session.make_end_of_cycle_updates_if_needed(
            plan, self.next_year - timedelta(days=1)
        )
        self.assertEqual(LicenseLedger.objects.count(), 1)
        # Plan needs to renew
        # TODO: do_deactivate_user for a user, so that licenses_at_next_renewal != licenses
        new_plan, ledger_entry = billing_session.make_end_of_cycle_updates_if_needed(
            plan, self.next_year
        )
        self.assertIsNone(new_plan)
        self.assertEqual(LicenseLedger.objects.count(), 2)
        ledger_params = {
            "plan": plan,
            "is_renewal": True,
            "event_time": self.next_year,
            "licenses": self.seat_count,
            "licenses_at_next_renewal": self.seat_count,
        }
        for key, value in ledger_params.items():
            self.assertEqual(getattr(ledger_entry, key), value)
        # Plan needs to renew, but we already added the plan_renewal ledger entry
        billing_session.make_end_of_cycle_updates_if_needed(
            plan, self.next_year + timedelta(days=1)
        )
        self.assertEqual(LicenseLedger.objects.count(), 2)

    def test_update_license_ledger_if_needed(self) -> None:
        realm = get_realm("zulip")
        billing_session = RealmBillingSession(user=None, realm=realm)
        # Test no Customer
        billing_session.update_license_ledger_if_needed(self.now)
        self.assertFalse(LicenseLedger.objects.exists())
        # Test plan not automanaged
        self.local_upgrade(
            self.seat_count + 1, False, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
        )
        plan = CustomerPlan.objects.get()
        self.assertEqual(LicenseLedger.objects.count(), 1)
        self.assertEqual(plan.licenses(), self.seat_count + 1)
        self.assertEqual(plan.licenses_at_next_renewal(), self.seat_count + 1)
        billing_session.update_license_ledger_if_needed(self.now)
        self.assertEqual(LicenseLedger.objects.count(), 1)
        # Test no active plan
        plan.automanage_licenses = True
        plan.status = CustomerPlan.ENDED
        plan.save(update_fields=["automanage_licenses", "status"])
        billing_session.update_license_ledger_if_needed(self.now)
        self.assertEqual(LicenseLedger.objects.count(), 1)
        # Test update needed
        plan.status = CustomerPlan.ACTIVE
        plan.save(update_fields=["status"])
        billing_session.update_license_ledger_if_needed(self.now)
        self.assertEqual(LicenseLedger.objects.count(), 2)

    def test_update_license_ledger_for_automanaged_plan(self) -> None:
        realm = get_realm("zulip")
        with time_machine.travel(self.now, tick=False):
            self.local_upgrade(
                self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
            )
        plan = CustomerPlan.objects.first()
        assert plan is not None
        self.assertEqual(plan.licenses(), self.seat_count)
        self.assertEqual(plan.licenses_at_next_renewal(), self.seat_count)

        billing_session = RealmBillingSession(user=None, realm=realm)
        # Simple increase
        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=23):
            billing_session.update_license_ledger_for_automanaged_plan(plan, self.now)
            self.assertEqual(plan.licenses(), 23)
            self.assertEqual(plan.licenses_at_next_renewal(), 23)
        # Decrease
        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=20):
            billing_session.update_license_ledger_for_automanaged_plan(plan, self.now)
            self.assertEqual(plan.licenses(), 23)
            self.assertEqual(plan.licenses_at_next_renewal(), 20)
        # Increase, but not past high watermark
        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=21):
            billing_session.update_license_ledger_for_automanaged_plan(plan, self.now)
            self.assertEqual(plan.licenses(), 23)
            self.assertEqual(plan.licenses_at_next_renewal(), 21)
        # Increase, but after renewal date, and below last year's high watermark
        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=22):
            billing_session.update_license_ledger_for_automanaged_plan(
                plan, self.next_year + timedelta(seconds=1)
            )
            self.assertEqual(plan.licenses(), 22)
            self.assertEqual(plan.licenses_at_next_renewal(), 22)

        ledger_entries = list(
            LicenseLedger.objects.values_list(
                "is_renewal", "event_time", "licenses", "licenses_at_next_renewal"
            ).order_by("id")
        )
        self.assertEqual(
            ledger_entries,
            [
                (True, self.now, self.seat_count, self.seat_count),
                (False, self.now, 23, 23),
                (False, self.now, 23, 20),
                (False, self.now, 23, 21),
                (True, self.next_year, 21, 21),
                (False, self.next_year + timedelta(seconds=1), 22, 22),
            ],
        )

    def test_update_license_ledger_for_manual_plan(self) -> None:
        realm = get_realm("zulip")

        with time_machine.travel(self.now, tick=False):
            self.local_upgrade(
                self.seat_count + 1, False, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
            )

        billing_session = RealmBillingSession(user=None, realm=realm)
        plan = get_current_plan_by_realm(realm)
        assert plan is not None

        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=self.seat_count):
            billing_session.update_license_ledger_for_manual_plan(
                plan, self.now, licenses=self.seat_count + 3
            )
            self.assertEqual(plan.licenses(), self.seat_count + 3)
            self.assertEqual(plan.licenses_at_next_renewal(), self.seat_count + 3)

        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=self.seat_count):
            with self.assertRaises(AssertionError):
                billing_session.update_license_ledger_for_manual_plan(
                    plan, self.now, licenses=self.seat_count
                )

        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=self.seat_count):
            billing_session.update_license_ledger_for_manual_plan(
                plan, self.now, licenses_at_next_renewal=self.seat_count
            )
            self.assertEqual(plan.licenses(), self.seat_count + 3)
            self.assertEqual(plan.licenses_at_next_renewal(), self.seat_count)

        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=self.seat_count):
            with self.assertRaises(AssertionError):
                billing_session.update_license_ledger_for_manual_plan(
                    plan, self.now, licenses_at_next_renewal=self.seat_count - 1
                )

        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=self.seat_count):
            billing_session.update_license_ledger_for_manual_plan(
                plan, self.now, licenses=self.seat_count + 10
            )
            self.assertEqual(plan.licenses(), self.seat_count + 10)
            self.assertEqual(plan.licenses_at_next_renewal(), self.seat_count + 10)

        billing_session.make_end_of_cycle_updates_if_needed(plan, self.next_year)
        self.assertEqual(plan.licenses(), self.seat_count + 10)

        ledger_entries = list(
            LicenseLedger.objects.values_list(
                "is_renewal", "event_time", "licenses", "licenses_at_next_renewal"
            ).order_by("id")
        )

        self.assertEqual(
            ledger_entries,
            [
                (True, self.now, self.seat_count + 1, self.seat_count + 1),
                (False, self.now, self.seat_count + 3, self.seat_count + 3),
                (False, self.now, self.seat_count + 3, self.seat_count),
                (False, self.now, self.seat_count + 10, self.seat_count + 10),
                (True, self.next_year, self.seat_count + 10, self.seat_count + 10),
            ],
        )

        with self.assertRaises(AssertionError):
            billing_session.update_license_ledger_for_manual_plan(plan, self.now)

    def test_user_changes(self) -> None:
        self.local_upgrade(self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False)
        user = do_create_user("email", "password", get_realm("zulip"), "name", acting_user=None)
        do_deactivate_user(user, acting_user=None)
        do_reactivate_user(user, acting_user=None)
        # Not a proper use of do_activate_mirror_dummy_user, but fine for this test
        do_activate_mirror_dummy_user(user, acting_user=None)
        ledger_entries = list(
            LicenseLedger.objects.values_list(
                "is_renewal", "licenses", "licenses_at_next_renewal"
            ).order_by("id")
        )
        self.assertEqual(
            ledger_entries,
            [
                (True, self.seat_count, self.seat_count),
                (False, self.seat_count + 1, self.seat_count + 1),
                (False, self.seat_count + 1, self.seat_count),
                (False, self.seat_count + 1, self.seat_count + 1),
                (False, self.seat_count + 1, self.seat_count + 1),
            ],
        )


class InvoiceTest(StripeTestCase):
    def test_invoicing_status_is_started(self) -> None:
        # local_upgrade uses hamlet as user, therefore realm is zulip.
        self.local_upgrade(self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False)
        plan = CustomerPlan.objects.first()
        assert plan is not None
        plan.invoicing_status = CustomerPlan.INVOICING_STATUS_STARTED
        plan.save(update_fields=["invoicing_status"])
        with self.assertRaises(NotImplementedError):
            billing_session = RealmBillingSession(realm=get_realm("zulip"))
            billing_session.invoice_plan(assert_is_not_none(CustomerPlan.objects.first()), self.now)

    def test_invoice_plan_without_stripe_customer(self) -> None:
        # local_upgrade uses hamlet as user, therefore realm is zulip.
        realm = get_realm("zulip")
        self.local_upgrade(
            self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, False, False
        )
        plan = get_current_plan_by_realm(realm)
        assert plan is not None
        plan.customer.stripe_customer_id = None
        plan.customer.save(update_fields=["stripe_customer_id"])
        with self.assertRaises(BillingError) as context:
            billing_session = RealmBillingSession(realm=realm)
            billing_session.invoice_plan(plan, timezone_now())
        self.assertRegex(
            context.exception.error_description,
            "Customer has a paid plan without a Stripe customer ID:",
        )

    @mock_stripe()
    def test_invoice_plan(self, *mocks: Mock) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)
        with time_machine.travel(self.now, tick=False):
            self.add_card_and_upgrade(user)
        realm = get_realm("zulip")
        billing_session = RealmBillingSession(user=user, realm=realm)
        # Increase
        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=self.seat_count + 3):
            billing_session.update_license_ledger_if_needed(self.now + timedelta(days=100))
        # Decrease
        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=self.seat_count):
            billing_session.update_license_ledger_if_needed(self.now + timedelta(days=200))
        # Increase, but not past high watermark
        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=self.seat_count + 1):
            billing_session.update_license_ledger_if_needed(self.now + timedelta(days=300))
        # Increase, but after renewal date, and below last year's high watermark
        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=self.seat_count + 2):
            billing_session.update_license_ledger_if_needed(self.now + timedelta(days=400))
        # Increase, but after event_time
        with patch("corporate.lib.stripe.get_latest_seat_count", return_value=self.seat_count + 3):
            billing_session.update_license_ledger_if_needed(self.now + timedelta(days=500))
        plan = CustomerPlan.objects.first()
        assert plan is not None
        billing_session.invoice_plan(plan, self.now + timedelta(days=400))
        stripe_customer_id = plan.customer.stripe_customer_id
        assert stripe_customer_id is not None
        [invoice0, invoice1] = iter(stripe.Invoice.list(customer=stripe_customer_id))
        self.assertIsNotNone(invoice0.status_transitions.finalized_at)
        [item0, item1, item2] = iter(invoice0.lines)
        line_item_params = {
            "amount": int(8000 * (1 - ((400 - 366) / 365)) + 0.5),
            "description": "Additional license (Feb 5, 2013 - Jan 2, 2014)",
            "discountable": False,
            "period": {
                "start": datetime_to_timestamp(self.now + timedelta(days=400)),
                "end": datetime_to_timestamp(self.now + timedelta(days=2 * 365 + 1)),
            },
            "quantity": 1,
        }
        for key, value in line_item_params.items():
            self.assertEqual(item0.get(key), value)
        line_item_params = {
            "amount": 8000 * (self.seat_count + 1),
            "description": "Zulip Cloud Standard - renewal",
            "discountable": False,
            "period": {
                "start": datetime_to_timestamp(self.now + timedelta(days=366)),
                "end": datetime_to_timestamp(self.now + timedelta(days=2 * 365 + 1)),
            },
            "quantity": self.seat_count + 1,
        }
        for key, value in line_item_params.items():
            self.assertEqual(item1.get(key), value)
        line_item_params = {
            "amount": 3 * int(8000 * (366 - 100) / 366 + 0.5),
            "description": "Additional license (Apr 11, 2012 - Jan 2, 2013)",
            "discountable": False,
            "period": {
                "start": datetime_to_timestamp(self.now + timedelta(days=100)),
                "end": datetime_to_timestamp(self.now + timedelta(days=366)),
            },
            "quantity": 3,
        }
        for key, value in line_item_params.items():
            self.assertEqual(item2.get(key), value)

    @mock_stripe()
    def test_fixed_price_plans(self, *mocks: Mock) -> None:
        # Also tests charge_automatically=False
        user = self.example_user("hamlet")
        self.login_user(user)
        with time_machine.travel(self.now, tick=False):
            self.upgrade(invoice=True)
        plan = CustomerPlan.objects.first()
        assert plan is not None
        plan.fixed_price = 100
        plan.price_per_license = 0
        plan.save(update_fields=["fixed_price", "price_per_license"])
        billing_session = RealmBillingSession(realm=user.realm)
        billing_session.invoice_plan(plan, self.next_year)
        stripe_customer_id = plan.customer.stripe_customer_id
        assert stripe_customer_id is not None
        [invoice0, invoice1] = iter(stripe.Invoice.list(customer=stripe_customer_id))
        self.assertEqual(invoice0.collection_method, "send_invoice")
        [item] = iter(invoice0.lines)
        line_item_params = {
            "amount": 100,
            "description": "Zulip Cloud Standard - renewal",
            "discountable": False,
            "period": {
                "start": datetime_to_timestamp(self.next_year),
                "end": datetime_to_timestamp(self.next_year + timedelta(days=365)),
            },
            "quantity": 1,
        }
        for key, value in line_item_params.items():
            self.assertEqual(item.get(key), value)

    def test_no_invoice_needed(self) -> None:
        # local_upgrade uses hamlet as user, therefore realm is zulip.
        with time_machine.travel(self.now, tick=False):
            self.local_upgrade(
                self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
            )
        plan = CustomerPlan.objects.first()
        assert plan is not None
        self.assertEqual(plan.next_invoice_date, self.next_month)
        # Test this doesn't make any calls to stripe.Invoice or stripe.InvoiceItem
        assert plan.customer.realm is not None
        billing_session = RealmBillingSession(realm=plan.customer.realm)
        billing_session.invoice_plan(plan, self.next_month)
        plan = CustomerPlan.objects.first()
        # Test that we still update next_invoice_date
        assert plan is not None
        self.assertEqual(plan.next_invoice_date, self.next_month + timedelta(days=29))

    def test_invoice_plans_as_needed(self) -> None:
        with time_machine.travel(self.now, tick=False):
            self.local_upgrade(
                self.seat_count, True, CustomerPlan.BILLING_SCHEDULE_ANNUAL, True, False
            )
        plan = CustomerPlan.objects.first()
        assert plan is not None
        self.assertEqual(plan.next_invoice_date, self.next_month)
        # Test nothing needed to be done
        with patch("corporate.lib.stripe.BillingSession.invoice_plan") as mocked:
            invoice_plans_as_needed(self.next_month - timedelta(days=1))
        mocked.assert_not_called()
        # Test something needing to be done
        invoice_plans_as_needed(self.next_month)
        plan = CustomerPlan.objects.first()
        assert plan is not None
        self.assertEqual(plan.next_invoice_date, self.next_month + timedelta(days=29))


class TestTestClasses(ZulipTestCase):
    def test_subscribe_realm_to_manual_license_management_plan(self) -> None:
        realm = get_realm("zulip")
        plan, ledger = self.subscribe_realm_to_manual_license_management_plan(
            realm, 50, 60, CustomerPlan.BILLING_SCHEDULE_ANNUAL
        )

        plan.refresh_from_db()
        self.assertEqual(plan.automanage_licenses, False)
        self.assertEqual(plan.billing_schedule, CustomerPlan.BILLING_SCHEDULE_ANNUAL)
        self.assertEqual(plan.tier, CustomerPlan.TIER_CLOUD_STANDARD)
        self.assertEqual(plan.licenses(), 50)
        self.assertEqual(plan.licenses_at_next_renewal(), 60)

        ledger.refresh_from_db()
        self.assertEqual(ledger.plan, plan)
        self.assertEqual(ledger.licenses, 50)
        self.assertEqual(ledger.licenses_at_next_renewal, 60)

        realm.refresh_from_db()
        self.assertEqual(realm.plan_type, Realm.PLAN_TYPE_STANDARD)

    def test_subscribe_realm_to_monthly_plan_on_manual_license_management(self) -> None:
        realm = get_realm("zulip")
        plan, ledger = self.subscribe_realm_to_monthly_plan_on_manual_license_management(
            realm, 20, 30
        )

        plan.refresh_from_db()
        self.assertEqual(plan.automanage_licenses, False)
        self.assertEqual(plan.billing_schedule, CustomerPlan.BILLING_SCHEDULE_MONTHLY)
        self.assertEqual(plan.tier, CustomerPlan.TIER_CLOUD_STANDARD)
        self.assertEqual(plan.licenses(), 20)
        self.assertEqual(plan.licenses_at_next_renewal(), 30)

        ledger.refresh_from_db()
        self.assertEqual(ledger.plan, plan)
        self.assertEqual(ledger.licenses, 20)
        self.assertEqual(ledger.licenses_at_next_renewal, 30)

        realm.refresh_from_db()
        self.assertEqual(realm.plan_type, Realm.PLAN_TYPE_STANDARD)


class TestRealmBillingSession(StripeTestCase):
    def test_get_audit_log_error(self) -> None:
        user = self.example_user("hamlet")
        billing_session = RealmBillingSession(user)
        fake_audit_log = typing.cast(AuditLogEventType, 0)
        with self.assertRaisesRegex(
            BillingSessionAuditLogEventError, "Unknown audit log event type: 0"
        ):
            billing_session.get_audit_log_event(event_type=fake_audit_log)

    def test_get_customer(self) -> None:
        user = self.example_user("hamlet")
        billing_session = RealmBillingSession(user)
        customer = billing_session.get_customer()
        self.assertEqual(customer, None)

        customer = Customer.objects.create(realm=user.realm, stripe_customer_id="cus_12345")
        self.assertEqual(billing_session.get_customer(), customer)


class TestRemoteRealmBillingSession(StripeTestCase):
    def test_current_count_for_billed_licenses(self) -> None:
        server_uuid = str(uuid.uuid4())
        remote_server = RemoteZulipServer.objects.create(
            uuid=server_uuid,
            api_key="magic_secret_api_key",
            hostname="demo.example.com",
            contact_email="email@example.com",
        )
        realm_uuid = str(uuid.uuid4())
        remote_realm = RemoteRealm.objects.create(
            server=remote_server,
            uuid=realm_uuid,
            uuid_owner_secret="dummy-owner-secret",
            host="dummy-hostname",
            realm_date_created=timezone_now(),
        )
        billing_session = RemoteRealmBillingSession(remote_realm=remote_realm)

        # remote server never uploaded statistics. 'last_audit_log_update' is None.
        with self.assertRaises(MissingDataError):
            billing_session.current_count_for_billed_licenses()

        # Available statistics is stale.
        remote_server.last_audit_log_update = timezone_now() - timedelta(days=5)
        remote_server.save()
        with self.assertRaises(MissingDataError):
            billing_session.current_count_for_billed_licenses()

        # Available statistics is not stale.
        event_time = timezone_now() - timedelta(days=1)
        data_list = [
            {
                "server": remote_server,
                "remote_realm": remote_realm,
                "event_type": RemoteRealmAuditLog.USER_CREATED,
                "event_time": event_time,
                "extra_data": {
                    RemoteRealmAuditLog.ROLE_COUNT: {
                        RemoteRealmAuditLog.ROLE_COUNT_HUMANS: {
                            UserProfile.ROLE_REALM_ADMINISTRATOR: 10,
                            UserProfile.ROLE_REALM_OWNER: 10,
                            UserProfile.ROLE_MODERATOR: 10,
                            UserProfile.ROLE_MEMBER: 10,
                            UserProfile.ROLE_GUEST: 10,
                        }
                    }
                },
            },
            {
                "server": remote_server,
                "remote_realm": remote_realm,
                "event_type": RemoteRealmAuditLog.USER_ROLE_CHANGED,
                "event_time": event_time,
                "extra_data": {
                    RemoteRealmAuditLog.ROLE_COUNT: {
                        RemoteRealmAuditLog.ROLE_COUNT_HUMANS: {
                            UserProfile.ROLE_REALM_ADMINISTRATOR: 20,
                            UserProfile.ROLE_REALM_OWNER: 10,
                            UserProfile.ROLE_MODERATOR: 0,
                            UserProfile.ROLE_MEMBER: 30,
                            UserProfile.ROLE_GUEST: 10,
                        }
                    }
                },
            },
        ]
        RemoteRealmAuditLog.objects.bulk_create([RemoteRealmAuditLog(**data) for data in data_list])
        remote_server.last_audit_log_update = timezone_now() - timedelta(days=1)
        remote_server.save()

        self.assertEqual(billing_session.current_count_for_billed_licenses(), 70)


class TestRemoteServerBillingSession(StripeTestCase):
    def test_get_audit_log_error(self) -> None:
        server_uuid = str(uuid.uuid4())
        remote_server = RemoteZulipServer.objects.create(
            uuid=server_uuid,
            api_key="magic_secret_api_key",
            hostname="demo.example.com",
            contact_email="email@example.com",
        )
        billing_session = RemoteServerBillingSession(remote_server)
        fake_audit_log = typing.cast(AuditLogEventType, 0)
        with self.assertRaisesRegex(
            BillingSessionAuditLogEventError, "Unknown audit log event type: 0"
        ):
            billing_session.get_audit_log_event(event_type=fake_audit_log)

    def test_get_customer(self) -> None:
        server_uuid = str(uuid.uuid4())
        remote_server = RemoteZulipServer.objects.create(
            uuid=server_uuid,
            api_key="magic_secret_api_key",
            hostname="demo.example.com",
            contact_email="email@example.com",
        )
        billing_session = RemoteServerBillingSession(remote_server)
        customer = billing_session.get_customer()
        self.assertEqual(customer, None)

        customer = Customer.objects.create(
            remote_server=remote_server, stripe_customer_id="cus_12345"
        )
        self.assertEqual(billing_session.get_customer(), customer)

    # @mock_stripe
    # def test_update_or_create_stripe_customer(self) -> None:
    #     server_uuid = str(uuid.uuid4())
    #     remote_server = RemoteZulipServer.objects.create(
    #         uuid=server_uuid,
    #         api_key="magic_secret_api_key",
    #         hostname="demo.example.com",
    #         contact_email="email@example.com",
    #     )
    #     billing_session = RemoteServerBillingSession(remote_server)
    #     # We need to generate stripe fixture for this type of test.
    #     customer = billing_session.update_or_create_stripe_customer()
    #     assert customer.stripe_customer_id
    #     # Confirm audit log, etc.


class TestSupportBillingHelpers(StripeTestCase):
    @mock_stripe()
    def test_attach_discount_to_realm(self, *mocks: Mock) -> None:
        # Attach discount before Stripe customer exists
        support_admin = self.example_user("iago")
        user = self.example_user("hamlet")
        billing_session = RealmBillingSession(support_admin, realm=user.realm, support_session=True)
        billing_session.attach_discount_to_customer(Decimal(85))
        realm_audit_log = RealmAuditLog.objects.filter(
            event_type=RealmAuditLog.REALM_DISCOUNT_CHANGED
        ).last()
        assert realm_audit_log is not None
        expected_extra_data = {"old_discount": None, "new_discount": str(Decimal("85"))}
        self.assertEqual(realm_audit_log.extra_data, expected_extra_data)
        self.login_user(user)
        # Check that the discount appears in page_params
        self.assert_in_success_response(["85"], self.client_get("/upgrade/"))
        # Check that the customer was charged the discounted amount
        self.add_card_and_upgrade(user)
        customer = Customer.objects.first()
        assert customer is not None
        [charge] = iter(stripe.Charge.list(customer=customer.stripe_customer_id))
        self.assertEqual(1200 * self.seat_count, charge.amount)
        stripe_customer_id = customer.stripe_customer_id
        assert stripe_customer_id is not None
        [invoice] = iter(stripe.Invoice.list(customer=stripe_customer_id))
        self.assertEqual(
            [1200 * self.seat_count, -1200 * self.seat_count],
            [item.amount for item in invoice.lines],
        )
        # Check CustomerPlan reflects the discount
        plan = CustomerPlan.objects.get(price_per_license=1200, discount=Decimal(85))

        # Attach discount to existing Stripe customer
        plan.status = CustomerPlan.ENDED
        plan.save(update_fields=["status"])
        billing_session = RealmBillingSession(support_admin, realm=user.realm, support_session=True)
        billing_session.attach_discount_to_customer(Decimal(25))
        with time_machine.travel(self.now, tick=False):
            self.add_card_and_upgrade(
                user, license_management="automatic", billing_modality="charge_automatically"
            )
        [charge, _] = iter(stripe.Charge.list(customer=customer.stripe_customer_id))
        self.assertEqual(6000 * self.seat_count, charge.amount)
        stripe_customer_id = customer.stripe_customer_id
        assert stripe_customer_id is not None
        [invoice, _] = iter(stripe.Invoice.list(customer=stripe_customer_id))
        self.assertEqual(
            [6000 * self.seat_count, -6000 * self.seat_count],
            [item.amount for item in invoice.lines],
        )
        plan = CustomerPlan.objects.get(price_per_license=6000, discount=Decimal(25))

        billing_session = RealmBillingSession(support_admin, realm=user.realm, support_session=True)
        billing_session.attach_discount_to_customer(Decimal(50))
        plan.refresh_from_db()
        self.assertEqual(plan.price_per_license, 4000)
        self.assertEqual(plan.discount, 50)
        customer.refresh_from_db()
        self.assertEqual(customer.default_discount, 50)
        invoice_plans_as_needed(self.next_year + timedelta(days=10))
        stripe_customer_id = customer.stripe_customer_id
        assert stripe_customer_id is not None
        [invoice, _, _] = iter(stripe.Invoice.list(customer=stripe_customer_id))
        self.assertEqual([4000 * self.seat_count], [item.amount for item in invoice.lines])
        realm_audit_log = RealmAuditLog.objects.filter(
            event_type=RealmAuditLog.REALM_DISCOUNT_CHANGED
        ).last()
        assert realm_audit_log is not None
        expected_extra_data = {
            "old_discount": str(Decimal("25.0000")),
            "new_discount": str(Decimal("50")),
        }
        self.assertEqual(realm_audit_log.extra_data, expected_extra_data)
        self.assertEqual(realm_audit_log.acting_user, support_admin)

    def test_approve_realm_sponsorship(self) -> None:
        realm = get_realm("zulip")
        self.assertNotEqual(realm.plan_type, Realm.PLAN_TYPE_STANDARD_FREE)

        support_admin = self.example_user("iago")
        billing_session = RealmBillingSession(user=support_admin, realm=realm, support_session=True)
        billing_session.approve_sponsorship()
        self.assertEqual(realm.plan_type, Realm.PLAN_TYPE_STANDARD_FREE)

        expected_message = (
            "Your organization's request for sponsored hosting has been approved! You have been upgraded to Zulip Cloud Standard, free of charge. :tada:"
            "\n\nIf you could [list Zulip as a sponsor on your website](/help/linking-to-zulip-website), we would really appreciate it!"
        )
        sender = get_system_bot(settings.NOTIFICATION_BOT, realm.id)

        # Organization owners get the notification bot message
        desdemona_recipient = self.example_user("desdemona").recipient
        message_to_owner = Message.objects.filter(
            realm_id=realm.id, sender=sender.id, recipient=desdemona_recipient
        ).first()
        assert message_to_owner is not None
        self.assertEqual(message_to_owner.content, expected_message)
        self.assertEqual(message_to_owner.recipient.type, Recipient.PERSONAL)

        # Organization billing admins get the notification bot message
        hamlet_recipient = self.example_user("hamlet").recipient
        message_to_billing_admin = Message.objects.filter(
            realm_id=realm.id, sender=sender.id, recipient=hamlet_recipient
        ).first()
        assert message_to_billing_admin is not None
        self.assertEqual(message_to_billing_admin.content, expected_message)
        self.assertEqual(message_to_billing_admin.recipient.type, Recipient.PERSONAL)

    def test_update_realm_sponsorship_status(self) -> None:
        lear = get_realm("lear")
        iago = self.example_user("iago")
        billing_session = RealmBillingSession(user=iago, realm=lear, support_session=True)
        billing_session.update_customer_sponsorship_status(True)
        customer = get_customer_by_realm(realm=lear)
        assert customer is not None
        self.assertTrue(customer.sponsorship_pending)
        realm_audit_log = RealmAuditLog.objects.filter(
            event_type=RealmAuditLog.REALM_SPONSORSHIP_PENDING_STATUS_CHANGED
        ).last()
        assert realm_audit_log is not None
        expected_extra_data = {"sponsorship_pending": True}
        self.assertEqual(realm_audit_log.extra_data, expected_extra_data)
        self.assertEqual(realm_audit_log.acting_user, iago)

    def test_update_realm_billing_modality(self) -> None:
        realm = get_realm("zulip")
        customer = Customer.objects.create(realm=realm, stripe_customer_id="cus_12345")
        plan = CustomerPlan.objects.create(
            customer=customer,
            status=CustomerPlan.ACTIVE,
            billing_cycle_anchor=timezone_now(),
            billing_schedule=CustomerPlan.BILLING_SCHEDULE_ANNUAL,
            tier=CustomerPlan.TIER_CLOUD_STANDARD,
        )
        self.assertEqual(plan.charge_automatically, False)

        support_admin = self.example_user("iago")
        billing_session = RealmBillingSession(user=support_admin, realm=realm, support_session=True)
        billing_session.update_billing_modality_of_current_plan(True)
        plan.refresh_from_db()
        self.assertEqual(plan.charge_automatically, True)
        realm_audit_log = RealmAuditLog.objects.filter(
            event_type=RealmAuditLog.REALM_BILLING_MODALITY_CHANGED
        ).last()
        assert realm_audit_log is not None
        expected_extra_data = {"charge_automatically": plan.charge_automatically}
        self.assertEqual(realm_audit_log.acting_user, support_admin)
        self.assertEqual(realm_audit_log.extra_data, expected_extra_data)

        billing_session.update_billing_modality_of_current_plan(False)
        plan.refresh_from_db()
        self.assertEqual(plan.charge_automatically, False)
        realm_audit_log = RealmAuditLog.objects.filter(
            event_type=RealmAuditLog.REALM_BILLING_MODALITY_CHANGED
        ).last()
        assert realm_audit_log is not None
        expected_extra_data = {"charge_automatically": plan.charge_automatically}
        self.assertEqual(realm_audit_log.acting_user, support_admin)
        self.assertEqual(realm_audit_log.extra_data, expected_extra_data)

    @mock_stripe()
    def test_switch_realm_from_standard_to_plus_plan(self, *mocks: Mock) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)
        self.add_card_and_upgrade(user)
        customer = get_customer_by_realm(user.realm)
        assert customer is not None
        original_plan = get_current_plan_by_customer(customer)
        assert original_plan is not None
        self.assertEqual(original_plan.tier, CustomerPlan.TIER_CLOUD_STANDARD)

        support_admin = self.example_user("iago")
        billing_session = RealmBillingSession(
            user=support_admin, realm=user.realm, support_session=True
        )
        support_request = SupportViewRequest(
            support_type=SupportType.modify_plan,
            plan_modification="upgrade_plan_tier",
            new_plan_tier=CustomerPlan.TIER_CLOUD_PLUS,
        )
        success_message = billing_session.process_support_view_request(support_request)
        self.assertEqual(success_message, "zulip upgraded to Zulip Cloud Plus")
        customer.refresh_from_db()
        new_plan = get_current_plan_by_customer(customer)
        assert new_plan is not None
        self.assertEqual(new_plan.tier, CustomerPlan.TIER_CLOUD_PLUS)

    @mock_stripe()
    def test_downgrade_realm_and_void_open_invoices(self, *mocks: Mock) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)
        with time_machine.travel(self.now, tick=False):
            self.upgrade(invoice=True)
        customer = get_customer_by_realm(user.realm)
        assert customer is not None
        original_plan = get_current_plan_by_customer(customer)
        assert original_plan is not None
        self.assertEqual(original_plan.status, CustomerPlan.ACTIVE)

        support_admin = self.example_user("iago")
        billing_session = RealmBillingSession(
            user=support_admin, realm=user.realm, support_session=True
        )
        support_request = SupportViewRequest(
            support_type=SupportType.modify_plan,
            plan_modification="downgrade_now_void_open_invoices",
        )
        success_message = billing_session.process_support_view_request(support_request)
        self.assertEqual(success_message, "zulip downgraded and voided 1 open invoices")
        original_plan.refresh_from_db()
        self.assertEqual(original_plan.status, CustomerPlan.ENDED)