Mock mongo event tracking backend during tests

common/djangoapps/track/backends/tests/test_mongodb.py

@@ -2,7 +2,7 @@
 
 from uuid import uuid4
 
-import pymongo
+from mock import patch
 
 from django.test import TestCase
 
@@ -11,33 +11,30 @@
 
 class TestMongoBackend(TestCase):
     def setUp(self):
-        # Use a random database name to prevent problems with tests running
-        # simultenousely against the same mongo instance
-        database = '_track_backends_mongodb_{0}'.format(uuid4().hex)
-        collection = '_test'
+        self.mongo_patcher = patch('track.backends.mongodb.MongoClient')
+        self.addCleanup(self.mongo_patcher.stop)
+        self.mongo_patcher.start()
 
-        self.connection = pymongo.MongoClient()
-        self.database = self.connection[database]
-        self.collection = self.database[collection]
+        self.backend = MongoBackend()
 
-        # During tests, wait until mongo acknowledged the write
-        write_concern = 1
+    def test_mongo_backend(self):
+        events = [{'test': 1}, {'test': 2}]
 
-        self.backend = MongoBackend(
-            database=database,
-            collection=collection,
-            w=write_concern
-        )
+        self.backend.send(events[0])
+        self.backend.send(events[1])
 
-    def test_mongo_backend(self):
-        self.backend.send({'test': 1})
-        self.backend.send({'test': 2})
+        # Check if we inserted events into the database
+
+        calls = self.backend.collection.insert.mock_calls
+
+        self.assertEqual(len(calls), 2)
 
-        # Get all the objects in the db ignoring _id
-        results = list(self.collection.find({}, {'_id': False}))
+        # Unpack the arguments and check if the events were used
+        # as the first argument to collection.insert
 
-        self.assertEqual(len(results), 2)
-        self.assertEqual(results, [{'test': 1}, {'test': 2}])
+        def first_argument(call):
+            _, args, _ = call
+            return args[0]
 
-    def tearDown(self):
-        self.connection.drop_database(self.database)
+        self.assertEqual(events[0], first_argument(calls[0]))
+        self.assertEqual(events[1], first_argument(calls[1]))