'assert that the mock was never called.'

def assert_not_called(_mock_self):

    self = _mock_self
    if (self.call_count != 0):
        msg = ("Expected    '%s'    to    not    have    been    called.    Called    %s    times." % ((self._mock_name or 'mock'), self.call_count))
        raise AssertionError(msg)
