python - 在派生类中覆盖 assertEqual 时出现 TypeError

Question

我用我自己的类覆盖unittest.TestCase，我想在其中添加一些额外的功能assertEqual：

class MyTestCase(unittest.TestCase):        
    def __init__(self,*args, **kwargs):
        unittest.TestCase.__init__(self, *args, **kwargs)

    def _write_to_log(self):
        print "writing to log..."

    def assertEqual(self, first, second, msg=None):
        self._write_to_log()
        unittest.TestCase.assertEqual(first, second, msg)

但我得到了TypeError: unbound method assertEqual() must be called with TestCase instance as first argument (got int instance instead)？

Answer 1

您忘记传递self给assertEqual：

unittest.TestCase.assertEqual(self, first, second, msg)

您应该super()在整个覆盖过程中真正使用：

class MyTestCase(unittest.TestCase):        
    def __init__(self,*args, **kwargs):
        super(MyTestCase, self).__init__(*args, **kwargs)

    def assertEqual(self, first, second, msg=None):
        self._write_to_log()
        super(MyTestCase, self).assertEqual(first, second, msg)

Answer 2

您assertEqual作为类方法调用，而不传递实例：这就是 Python 抱怨该方法未绑定的原因。

您可能应该使用：

super(MyTestCase, self).assertEqual(first, second, msg)