hipchat import: Start adding tests.

These test are for the handling of HipChat
sender info.  The data formats are somewhat
inconsistent and sometimes require us to
generate "mirror" users, so this is potentially
fragile code if we don't cover it well.

zerver/tests/test_hipchat_importer.py

@@ -0,0 +1,55 @@
+from zerver.data_import.hipchat import (
+    get_hipchat_sender_id,
+)
+from zerver.data_import.hipchat_user import (
+    UserHandler,
+)
+
+from zerver.lib.test_classes import (
+    ZulipTestCase,
+)
+from typing import Any, Dict
+
+
+class HipChatImporter(ZulipTestCase):
+    def test_sender_ids(self) -> None:
+        realm_id = 5
+        user_handler = UserHandler()
+
+        # Simulate a "normal" user first.
+        user_with_id = dict(
+            id=1,
+            # other fields don't matter here
+        )
+        user_handler.add_user(user=user_with_id)
+
+        normal_message = dict(
+            sender=dict(
+                id=1,
+            )
+        )  # type: Dict[str, Any]
+
+        sender_id = get_hipchat_sender_id(
+            realm_id=realm_id,
+            message_dict=normal_message,
+            user_handler=user_handler,
+        )
+
+        self.assertEqual(sender_id, 1)
+
+        bot_message = dict(
+            sender='fred_bot',
+        )
+
+        # Every message from fred_bot should
+        # return the same sender_id.
+        fred_bot_sender_id = 2
+
+        for i in range(3):
+            sender_id = get_hipchat_sender_id(
+                realm_id=realm_id,
+                message_dict=bot_message,
+                user_handler=user_handler,
+            )
+
+            self.assertEqual(sender_id, fred_bot_sender_id)