From c7e33c6c9fedb150126b7f1bf066211e15b4117b Mon Sep 17 00:00:00 2001
From: Tommy Ip <hkmp7tommy@gmail.com>
Date: Thu, 9 Feb 2017 21:58:43 +0000
Subject: [PATCH] optimization: Use Python to test management commands.

The original test was written in shell script which launches a new
django instance for every tests. By doing it in Python, we avoid
the overhead and reduce the test time to <1 second.

Fixes #3620.
---
 tools/test-all                           |  2 --
 tools/test-management                    | 18 ------------
 tools/travis/backend                     |  2 --
 zerver/lib/test_helpers.py               | 10 +++++++
 zerver/tests/test_management_commands.py | 36 +++++++++++++++++++++---
 5 files changed, 42 insertions(+), 26 deletions(-)
 delete mode 100755 tools/test-management

diff --git a/tools/test-all b/tools/test-all
index 3af9885feb..7dacc0a668 100755
--- a/tools/test-all
+++ b/tools/test-all
@@ -39,8 +39,6 @@ run ./tools/test-js-with-node
 run ./tools/run-mypy
 run ./tools/test-backend $FORCEARG
 run ./tools/test-js-with-casper $FORCEARG
-# Not running management test since it takes 40s and thus is too slow to be worth it.
-# run ./tools/test-management
 # Not running queue worker reload tests since it's low-churn code
 # run ./tools/test-queue-worker-reload
 # Not running documentation tests since it takes 20s and only tests documentation
diff --git a/tools/test-management b/tools/test-management
deleted file mode 100755
index 5451bea2fa..0000000000
--- a/tools/test-management
+++ /dev/null
@@ -1,18 +0,0 @@
-#!/bin/bash
-set -e
-
-echo "Testing management commands start!"
-failed=0
-for i in `ls */management/commands/ | grep .py$ | grep -v __init__ | sed 's/[.]py$//'`; do
-    if ! $(./manage.py $i --help >/dev/null); then
-        failed=$(expr $failed + 1)
-        echo "ERROR: \`./manage.py $i --help\` crashes!";
-    fi
-done
-
-if [ $failed -gt 0 ]; then
-   echo
-   echo "$failed management commands don't start!"
-   exit 1
-fi
-echo "All management commands start!"
diff --git a/tools/travis/backend b/tools/travis/backend
index 85eddfb6e7..2905ec3395 100755
--- a/tools/travis/backend
+++ b/tools/travis/backend
@@ -7,7 +7,6 @@ set -x
 
 ./tools/lint-all --pep8 # Include the slow and thus non-default pep8 linter check
 ./tools/test-backend --coverage --no-verbose-coverage
-./tools/test-management
 ./tools/test-migrations
 ./tools/test-run-dev
 ./tools/test-documentation
@@ -15,4 +14,3 @@ set -x
 ./tools/test-api
 # Some test suites disabled in CI for being flaky
 #./tools/test-queue-worker-reload
-
diff --git a/zerver/lib/test_helpers.py b/zerver/lib/test_helpers.py
index bb60ba5bb8..5f457638a6 100644
--- a/zerver/lib/test_helpers.py
+++ b/zerver/lib/test_helpers.py
@@ -163,6 +163,16 @@ def queries_captured(include_savepoints=False):
     TimeTrackingCursor.execute = old_execute # type: ignore # https://github.com/JukkaL/mypy/issues/1167
     TimeTrackingCursor.executemany = old_executemany # type: ignore # https://github.com/JukkaL/mypy/issues/1167
 
+@contextmanager
+def stdout_suppressed():
+    # type: () -> Iterator[IO[str]]
+    """Redirect stdout to /dev/null."""
+
+    with open(os.devnull, 'a') as devnull:
+        stdout, sys.stdout = sys.stdout, devnull  # type: ignore
+        yield stdout
+        sys.stdout = stdout
+
 def get_test_image_file(filename):
     # type: (str) -> IO[Any]
     test_avatar_dir = os.path.abspath(os.path.join(os.path.dirname(__file__), '../tests/images'))
diff --git a/zerver/tests/test_management_commands.py b/zerver/tests/test_management_commands.py
index 7873d1190d..25eca8eb51 100644
--- a/zerver/tests/test_management_commands.py
+++ b/zerver/tests/test_management_commands.py
@@ -1,13 +1,41 @@
 # -*- coding: utf-8 -*-
+from __future__ import absolute_import, print_function
+
 import os
-from mock import patch, MagicMock
-from django.test import TestCase
+import glob
+from datetime import timedelta
+from mock import MagicMock, patch
+from six.moves import map, filter
+
 from django.conf import settings
 from django.core.management import call_command
+from django.test import TestCase
+from zerver.lib.test_classes import ZulipTestCase
+from zerver.lib.test_helpers import stdout_suppressed
 from zerver.models import get_realm
 from confirmation.models import RealmCreationKey, generate_realm_creation_url
-from datetime import timedelta
-from zerver.lib.test_classes import ZulipTestCase
+
+class TestCommandsCanStart(TestCase):
+
+    def setUp(self):
+        # type: () -> None
+        self.commands = filter(
+            lambda filename: filename != '__init__',
+            map(
+                lambda file: os.path.basename(file).replace('.py', ''),
+                glob.iglob('*/management/commands/*.py')
+            )
+        )
+
+    def test_management_commands_show_help(self):
+        # type: () -> None
+        with stdout_suppressed() as stdout:
+            for command in self.commands:
+                print('Testing management command: {}'.format(command),
+                      file=stdout)
+
+                with self.assertRaises(SystemExit):
+                    call_command(command, '--help')
 
 class TestSendWebhookFixtureMessage(TestCase):
     COMMAND_NAME = 'send_webhook_fixture_message'