Fixed closing connections in test_utils.tests.AllowedDatabaseQueriesTests.

tests/test_utils/tests.py

@@ -2132,12 +2132,34 @@ class AllowedDatabaseQueriesTests(SimpleTestCase):
         next(Car.objects.iterator(), None)
 
     def test_allowed_threaded_database_queries(self):
+        connections_dict = {}
+
         def thread_func():
+            # Passing django.db.connection between threads doesn't work while
+            # connections[DEFAULT_DB_ALIAS] does.
+            from django.db import connections
+
+            connection = connections["default"]
+
             next(Car.objects.iterator(), None)
 
-        t = threading.Thread(target=thread_func)
-        t.start()
-        t.join()
+            # Allow thread sharing so the connection can be closed by the main
+            # thread.
+            connection.inc_thread_sharing()
+            connections_dict[id(connection)] = connection
+
+        try:
+            t = threading.Thread(target=thread_func)
+            t.start()
+            t.join()
+        finally:
+            # Finish by closing the connections opened by the other threads
+            # (the connection opened in the main thread will automatically be
+            # closed on teardown).
+            for conn in connections_dict.values():
+                if conn is not connection and conn.allow_thread_sharing:
+                    conn.close()
+                    conn.dec_thread_sharing()
 
 
 class DatabaseAliasTests(SimpleTestCase):