Explicitly use mock credentials (for Travis).

Author: Luke Sneeringer

spanner/unit_tests/test_client.py

@@ -123,7 +123,7 @@ def test_admin_api_lib_name(self):
         # name and version.
         with mock.patch.object(DatabaseAdminClient, '__init__') as mock_dac:
             mock_dac.return_value = None
-            client = self._make_one()
+            client = self._make_one(credentials=_make_credentials())
             self.assertIsInstance(client.database_admin_api,
                                   DatabaseAdminClient)
             mock_dac.assert_called_once()
@@ -135,7 +135,7 @@ def test_admin_api_lib_name(self):
         # name and version.
         with mock.patch.object(InstanceAdminClient, '__init__') as mock_iac:
             mock_iac.return_value = None
-            client = self._make_one()
+            client = self._make_one(credentials=_make_credentials())
             self.assertIsInstance(client.instance_admin_api,
                                   InstanceAdminClient)
             mock_iac.assert_called_once()