Add tests

mongoengine/connection.py

@@ -245,6 +245,7 @@ def get_connection(alias=DEFAULT_CONNECTION_NAME, reconnect=False):
         }
 
     raw_conn_settings = _connection_settings[alias].copy()
+
     # Retrieve a copy of the connection settings associated with the requested
     # alias and remove the database name and authentication info (we don't
     # care about them at this point).
@@ -269,22 +270,20 @@ def get_connection(alias=DEFAULT_CONNECTION_NAME, reconnect=False):
     if existing_connection:
         _connections[alias] = existing_connection
     else:
-        # Otherwise, create the new connection for this alias. Raise
-        # MongoEngineConnectionError if it can't be established.
-        try:
-            _connections[alias] = connection_class(**conn_settings)
-        except Exception as e:
-            raise MongoEngineConnectionError(
-                'Cannot connect to database %s :\n%s' % (alias, e))
+        _create_connection(alias=alias,
+                           connection_class=connection_class,
+                           **conn_settings)
 
     return _connections[alias]
 
 
-def _create_connection(connection_class, **connection_settings):
-    # Otherwise, create the new connection for this alias. Raise
-    # MongoEngineConnectionError if it can't be established.
+def _create_connection(alias, connection_class, **connection_settings):
+    """
+    Create the new connection for this alias. Raise
+    MongoEngineConnectionError if it can't be established.
+    """
     try:
-        _connections[alias] = connection_class(**conn_settings)
+        _connections[alias] = connection_class(**connection_settings)
     except Exception as e:
         raise MongoEngineConnectionError(
             'Cannot connect to database %s :\n%s' % (alias, e))
@@ -300,7 +299,7 @@ def _find_existing_connection(connection_settings):
     :param connection_settings: the settings of the new connection
     :return: An existing connection or None
     """
-    connection_settings_iterator = (
+    connection_settings_bis = (
         (db_alias, settings.copy())
         for db_alias, settings in _connection_settings.items()
     )
@@ -312,7 +311,7 @@ def _find_existing_connection(connection_settings):
         return {k: v for k, v in settings_dict.items() if k != 'name'}
 
     cleaned_conn_settings = _clean_settings(connection_settings)
-    for db_alias, connection_settings in connection_settings_iterator:
+    for db_alias, connection_settings in connection_settings_bis:
         db_conn_settings = _clean_settings(connection_settings)
         if cleaned_conn_settings == db_conn_settings and _connections.get(db_alias):
             return _connections[db_alias]

tests/test_connection.py

@@ -611,6 +611,16 @@ class ConnectionTest(unittest.TestCase):
         self.assertEqual(mongo_connections['t1'].address[0], 'localhost')
         self.assertEqual(mongo_connections['t2'].address[0], '127.0.0.1')
 
+    def test_connect_2_databases_uses_same_client_if_only_dbname_differs(self):
+        c1 = connect(alias='testdb1', db='testdb1')
+        c2 = connect(alias='testdb2', db='testdb2')
+        self.assertIs(c1, c2)
+
+    def test_connect_2_databases_uses_different_client_if_different_parameters(self):
+        c1 = connect(alias='testdb1', db='testdb1', username='u1')
+        c2 = connect(alias='testdb2', db='testdb2', username='u2')
+        self.assertIsNot(c1, c2)
+
 
 if __name__ == '__main__':
     unittest.main()