Hi Philippe,
On Wed, Oct 28, 2009 at 08:09 +0100, Philippe Fremy wrote:
> holger krekel wrote:
> > Hi Frederik!
> >
> >> However, I've finally figured out why I'm having such a hard time
> >> warming up to funcargs: They go way beyond the minimalist simplicity
> >> that made me switch to py.test in the first place.
> >> (I realize there's some Magic to py.test's internals, but that doesn't
> >> surface in the API.)
> >>
> >> Funcargs seem like a departure from this principle.
> >> I understand that some situations demand such complexity, so I'm not
> >> arguing against funcargs in general - but for my part, I've managed to
> >> keep it simple so far.
> >>
> I second Frederic here. I chose py.test because of the overall
> simplicity of the framework when you use it. The
> setup_module/setup_class/setup_method without any special magic other
> than using function, class or method names starting with test is really
> really nice. I am kind of worried because I could no longer find them in
> the documentation. I eventually found them in the xUnit documentation
> but that's not where I expected them. I vote for a return of this
> documentation to the main py.test documentation, and moving funcarg
> related documentation to an "advanced test setup" section.
I am worried that newcomers will be confused then. But i see
the point of "unhiding" the xUnit documentation.
> funcarg seems to be a powerful tool, but really cumbersome to grok. I
> find the magic trick on the naming with __myargument a bit cumbersome. I
> would feel more comfortable with a syntax that mimic the setup/teardown
> used for module, class and methods.
It would be easy to also allow explicit registration for factories ala:
def pytest_configure(config):
config.add_funcarg_factory(name, factoryfunc)
but at the time i choose "convention over configuration" and the
"__" because Django also uses a similar way to encode values into
a function name.
> > This implies having to call magic methods for setting up objects in
> > global namespaces or 'self' attributes - which not only makes the test
> > harder to understand and refactor IMO.
>
> I do not agree here. If I have one class with 30 unit test methods, it's
> easier to setup/teardown the test parameters in two methods for the
> whole class than modifying 30 test methods to add funcargs arguments.
agreed, i am considering introducing a new hook:
def pytest_pyfunc_setup(request):
request.cached_setup(setupfunc, teardownfunc, scope="directory")
and this hook would be called for each python test function. Here
we call the cached_setup helper to help us manage setup/teardown scopes.
(see http://tinyurl.com/yfw82l5 for request object attributes
which you could pass into your setup/teardown func)
It would also mean you could write down:
class TestGroup:
parameter = 3
def test_method(self):
assert self.parametrized_obj ...
and implement a pytest_pyfunc_setup() to set a "self.someobj"
according to the class-specified parameter.
Would this make sense to you?
> So, while I agree that funcargs certainly has potential, I think you
> should not force it onto the user and should really stress the two ways
> of setting up per class or per method parameters.
ok, I'll see to work on the docs a bit.
> And it would be really nice to figure out a syntax for funcarg that is
> more in the setup/teardown fashion.
>
> I don't see much gain of using :
>
> def pytest_funcarg__mysetup(request):
> return MySetup(request)
>
> class TestClass:
> def test_function(self, mysetup):
> conn = mysetup.getsshconnection()
> # work with conn
>
>
> instead of :
>
> class TestClass:
> def setup_class( c ):
> c.mysetup = MySetup()
>
> def test_function(self):
> conn = c.mysetup.getsshconnection()
> # work with conn
>
>
> The programming style is different, the second one is traditional OO and
> will be familiar to anybody coming from C++, Java or other OO world. The
> second one is playing more on the python capabilities. I don't find it
> more readable.
If you have setup_module + setup_class + setup_method (+ subclassing!)
layers of setup and teardown, things get a bit harder to understand.
In >3000 test projects i know off this led to complexity and
refactoring difficulties.
> One can argue about the advantage that each test function can take a
> different parameter. While true, in my testing experience, I haven't
> seen a pattern with many different tests taking many different
> parameters. I usually have groups of 5 to 10 tests taking one kind of
> parameter. If they need to take another kind of parameter, I will put
> them in a different test class.
These days i sometimes group tests by feature rather than by setup-parameters.
E.g. i put two unit-tests and one functional test into a "TestFeature" class.
> So, in my opinion, using funcargs for regular cases is a matter of style.
>
> I do see a big value in funcargs for the parameterized tests. Running
> the same test over and over with different parameter is a really nice
> feature. I think you should stress it more in the documentation.
makes sense. thanks a lot for your feedback!
best,
holger
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