Question

使用Python的内置单元测试时，至少有2种不同的方式来组织班级设置，使用setUpClass()或仅使用老式的班级成员。什么时候使用，什么时候使用？

class TestFoo(unittest.TestCase):

    @classmethod
    def setUpClass(cls):
        cls.foo = Foo(...)

    def test_blah(self):
        self.foo.do_something()
        ...

VS

class TestFoo(unittest.TestCase):

    foo = Foo(...)

    def test_blah(self):
        self.foo.do_something()
        ...

Answer 1

实际上，除了您要使用@skipUnless(condition)装饰器之外，上述问题中的2个代码段基本上相同。

SETTINGS = json.load(...)

@unittest.skipUnless("foo" in SETTINGS, "skipped")
class TestFoo(unittest.TestCase):

    @classmethod
    def setUpClass(cls):
        cls.foo = Foo(SETTINGS["foo"])
# If SETTINGS["foo"] is undefined,
# this entire test class would be skipped

VS

SETTINGS = json.load(...)

@unittest.skipUnless("foo" in SETTINGS, "skipped")
class TestFoo(unittest.TestCase):

    foo = Foo(SETTINGS["foo"])
# This line will always be executed,
# BEFORE the skipUnless(...),
# so if SETTINGS["foo"] is undefined,
# there will be a runtime error here

什么时候应该使用setUpClass？何时只使用类成员？

1 个答案: