Fix assumptions in test_server_wait_method

test_server_wait_method was calling server.wait without having
previously called server.start and server.stop. This happened to work
because it also injected server._executor_obj. This is problematic,
though, as it assumes internal details of the server and does not
represent the calling contract of server.wait, which is that it must
follow server.stop (which must itself also follow server.start).

This change makes the necessary changes to call server.wait in the
correct sequence.

Change-Id: I205683ac6e0f2d64606bb06d08d3d1419f7645f4

oslo_messaging/tests/rpc/test_server.py

@@ -117,14 +117,23 @@ class TestRPCServer(test_utils.BaseTestCase, ServerSetupMixin):
         endpoints = [object()]
         serializer = object()
 
+        class MagicMockIgnoreArgs(mock.MagicMock):
+            '''A MagicMock which can never misinterpret the arguments passed to
+            it during construction.'''
+
+            def __init__(self, *args, **kwargs):
+                super(MagicMockIgnoreArgs, self).__init__()
+
         server = oslo_messaging.get_rpc_server(transport, target, endpoints,
                                                serializer=serializer)
         # Mocking executor
-        server._executor_obj = mock.Mock()
+        server._executor_cls = MagicMockIgnoreArgs
         # Here assigning executor's listener object to listener variable
         # before calling wait method, because in wait method we are
         # setting executor to None.
+        server.start()
         listener = server._executor_obj.listener
+        server.stop()
         # call server wait method
         server.wait()
         self.assertIsNone(server._executor_obj)