Unit test failing on master #123

___________________________ TestClient.test_constructor_implicit_credentials ____________________________

self = <tests.unit.test_client.TestClient testMethod=test_constructor_implicit_credentials>

    def test_constructor_implicit_credentials(self):
        creds = _make_credentials()
    
        patch = mock.patch("google.auth.default", return_value=(creds, None))
        with patch as default:
            self._constructor_test_helper(
                None, None, expected_creds=creds.with_scopes.return_value
            )
    
>       default.assert_called_once_with()

tests/unit/test_client.py:161: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
.nox/unit-2-7/lib/python2.7/site-packages/mock/mock.py:957: in assert_called_once_with
    return self.assert_called_with(*args, **kwargs)
.nox/unit-2-7/lib/python2.7/site-packages/mock/mock.py:944: in assert_called_with
    six.raise_from(AssertionError(_error_message(cause)), cause)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

value = AssertionError("expected call not found.\nExpected: default()\nActual: default(scopes=('https://www.googleapis.com/auth/spanner.admin',))",)
from_value = None

    def raise_from(value, from_value):
>       raise value
E       AssertionError: expected call not found.
E       Expected: default()
E       Actual: default(scopes=('https://www.googleapis.com/auth/spanner.admin',))

.nox/unit-2-7/lib/python2.7/site-packages/six.py:738: AssertionError