Python unittest setUpClass 无法从基类调用方法

Question

I am using the unittest framework from Python, and run into issues when setting up a class for a test case. I would like to call a method from the base class in the setUpClass() method as follows:

class TestA(unittest.TestCase):

    def __init__(self, *args, **kwargs):
        super(TestA, self).__init__(*args, **kwargs)

        self.variable = "hello"

    def do_something(self):
        print(self.variable)
        return self.variable

class TestB(TestA.TestA):

    @classmethod
    def setUpClass(cls):

        var = cls.do_something()

But I get an error saying that I cannot call do_something().

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

I have no idea how (and if) I can call a method from the base class as part of the setUpClass method.

What am I missing?

Answer 1

Use super() .

>>> class Base:
...     def do(self):
...             print('base is doing something')
... 
>>> class Child(Base):
...     def better_do(self):
...             super().do()
...             print('much better')
... 
>>> 
>>> c = Child()
>>> c.do()
base is doing something
>>> c.better_do()
base is doing something
much better
>>> 

A class method, however, is bit different. You must call the class itself.

>>> class Base:
...     @classmethod
...     def cls_do(cls):
...             print('Base class is doing something')
... 
>>> Base.cls_do()
Base class is doing something
>>>