python - 为pytest测试方法编写装饰器

Question

假设结构如下:

class SetupTestParam(object):
    def setup_method(self, method):
        self.foo = bar()

    @pytest.fixture
    def some_fixture():
        self.baz = 'foobar'

我使用 SetupTestParam 作为测试类的父类。

class TestSomething(SetupTestParam):
    def test_a_lot(self, some_fixture):
        with self.baz as magic:
            with magic.fooz as more_magic:
                 blah = more_magic.much_more_magic() # repetative bleh
            ... # not repetative code here
            assert spam == 'something cool'

现在，编写测试变得重复(使用语句)，我想编写一个装饰器来减少代码行数。但是 pytest 和函数签名有问题。

我发现了 library这应该会有帮助，但我无法让它工作。

我在我的 SetupTestParam 类中创建了一个 classmethod。

@classmethod
@decorator.decorator
def this_is_decorator(cls, f):
    def wrapper(self, *args, **kw):
        with self.baz as magic:
            with magic.fooz as more_magic:
                 blah = more_magic.much_more_magic() # repetative bleh
            return f(self, *args)
    return wrapper

装饰test_a_lot 方法后，我收到错误TypeError: transaction_decorator() takes exactly 1 argument (2 given)

有人可以解释一下我做错了什么吗？ (我假设测试方法中的 self 有问题？)

Answer 1

经过一些调整并意识到我需要将参数传递给装饰器后，我选择将其编写为一个类:

class ThisIsDecorator(object):
    def __init__(self, param):
        self.param = param   # Parameter may vary with the function being decorated
    def __call__(self, fn):
        wraps(fn) # [1]
        def wrapper(fn, fn_self, *args): # [2] fn_self refers to original self param from function fn (test_a_lot) [2]
            with fn_self.baz as fn_self.magic: # I pass magic to fn_self to make magic accesible in function fn (test_a_lot)
                with fn_self.magic.fooz as more_magic:
                    blah = self.param.much_more_magic() # repetative bleh
            return fn(fn_self, *args)
        return decorator.decorator(wrapper, fn) 

[1] 我用 wraps拥有原创fn __name__ , __module__和 __doc__ .

[2] 传递给 wrapper 的参数是self = <function test_a_lot at 0x24820c8> args = (<TestSomething object at 0x29c77d0>, None, None, None, None), kw = {}所以我拿出了args[0]作为fn_self .

原始版本(不传递参数):

 @classmethod
 def this_is_decorator(cls, fn):
     @wraps(fn)
     def wrapper(fn, fn_self, *args):
         with fn_self.baz as fn_self.magic:
             with fn_self.magic.fooz as more_magic:
                 blah = more_magic.much_more_magic() # repetative bleh
             return fn(fn_self, *args)
     return decorator.decorator(wrapper,fn)

感谢 Mike Muller 指出了正确的方向。