Restored a test broken by overzealous PEP8 cleanup

tests/backends/tests.py

@@ -388,6 +388,8 @@ class PostgresNewConnectionTests(TestCase):
         new_connection = new_connections[DEFAULT_DB_ALIAS]
         try:
             new_connection.settings_dict['AUTOCOMMIT'] = False
+            # Open a database connection.
+            new_connection.cursor()
             self.assertFalse(new_connection.get_autocommit())
         finally:
             new_connection.close()