Stuck on an issue?

Hi there.

I’d like to share my thought about using fixture in tests classes and maybe ask some advise. Current issue is related to two useful methods for newcomers from setuptools: (mark.usefixture and autouse - option for fixture) and using this stuff in Test classes.

First thing - (mark.usefixture) allows to define fixtures fro whole test class, but it does not provide ability to get access to this fixture from the test. For this purposes I have to define fixtures as parameters of test methods, like:

class TestExample():                  
    def test_one(self, param):               
        param.return_value = 100

honestly it’s not a big deal, when you have couple of the test. However for huge numbers of the test, where I have the same fixtures, I’d like to hide avoid using fixture parameter. So I have to do it in the such way:

class TestExample():                  
   @pytest.fixture(autouse=True)    
    def init_fixture(param1, param2):
        self.param1 = param1         
        self.param2 = param2         

    def test_one(self):               
        self.param1.return_value = 100
        self.param2.return_value = 200

So the main idea -to hide explicitly mentioned fixtures of the function and providing them as class attribute. It’s also can be useful, when you port some test from testscenario extension, where parameters are available as class attributes.

I suppose, that it can be done by improving “mark.usefixtures” decorator, where it allows to add fixtures as class attributes. So potentially decorator can have syntax, like: mark.usefixtures(*args, as_attrs=False), where *args - is list of fixtures, as previously and as_attrs is a flag (defailt is False), which save fixtures as class attributes. In case if function has not class it may be ignored or raise warning message.

Finally I suppose, that it can be done by adding minimal logic here: https://github.com/pytest-dev/pytest/blob/master/_pytest/python.py#L143

def pytest_pyfunc_call(pyfuncitem):                 
    testfunction = pyfuncitem.obj                   
+   if pyfuncitem.cls:
+         for k, v in pyfuncitem.funcargs:
+             setattr(pyfuncitem.cls, k, v) 
    if pyfuncitem._isyieldedfunction():             
        testfunction(*pyfuncitem._args)             
    else:                                           
        funcargs = pyfuncitem.funcargs              
        testargs = {}                               
        for arg in pyfuncitem._fixtureinfo.argnames:
            testargs[arg] = funcargs[arg]           
        testfunction(**testargs)                    
    return True        

Please correct me if I wrong somewhere or share your opinion about such change in the project.