def test_isMacOSX(self):
        """
        If a system platform name is supplied to L{Platform}'s initializer, it
        is used to determine the result of L{Platform.isMacOSX}, which returns
        C{True} for C{"darwin"}, C{False} otherwise.
        """
        self.assertTrue(Platform(None, 'darwin').isMacOSX())
        self.assertFalse(Platform(None, 'linux2').isMacOSX())
        self.assertFalse(Platform(None, 'win32').isMacOSX())

        If a system platform name is supplied to L{Platform}'s initializer, it
        is used to determine the result of L{Platform.isMacOSX}, which returns
        C{True} for C{"darwin"}, C{False} otherwise.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/python/test/test_runtime.py