无法从setUpClass调用本地方法

Question

我的代码:

class TestSystemPromotion(unittest2.TestCase):

  @classmethod
  def setUpClass(self):
    ...
    self.setup_test_data()
    ..

  def test_something(self):
    ...

  def setup_test_data(self):
    ...

if __name__ == '__main__':
  unittest2.main()

我得到的错误是:

TypeError: unbound method setup_test_data() must be called with TestSystemPromotion
instance as first argument (got nothing instead)

Answer 1

您无法从类方法中调用实例方法.或者考虑使用setUp,或者也可以setup_test_data使用类方法.此外,最好是调用参数cls而不是self避免混淆 - 类方法的第一个参数是类,而不是实例.调用self时,instance()根本不存在setUpClass.

class TestSystemPromotion(unittest2.TestCase):

  @classmethod
  def setUpClass(cls):
    cls.setup_test_data()


  @classmethod
  def setup_test_data(cls):
    ...

  def test_something(self):
    ...

要么:

class TestSystemPromotion(unittest2.TestCase):

  def setUp(self):
    self.setup_test_data()

  def setup_test_data(self):
    ...

  def test_something(self):
    ...

为了更好地理解,你可以这样想: cls == type(self)