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How do I write a decorator to skip certain tests when a module is not being imported?

I am using nose for testing. I know how to skip a test, but I was wondering if there is a simple solution for writing a decorator to skip tests when some module is not being imported.

I am currently trying to import the mock and catch ImportError

if it is not installed and installed mock = None

. At the beginning of tests that require mock, I use if not mock: raise SkipTest()

as the first line.

It works well. I'm just wondering if this is possible with a decorator too?

Update

I've been using the kind answer for some time now, just to notice today that it still doesn't work correctly (at least not all !

Seems to work when I use a test function that is not a generator (contains no instructions yield

). Whenever I use a decorator on a test function that uses yield

, though, the test passes regardless of whether assert

the resulting function fails .

Any ideas why this is happening and how to prevent this behavior?

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3 answers


Wouldn't it be like this job?



import functools

def requires_mock(test):

    @functools.wraps(test)
    def wrapper():
        if mock:
            return test()
        raise SkipTest

    return wrapper
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The decorator should look like this:

def needsMock(fn):
    def wrapped():
        if mock is None: return

        fn()

    return wrapped


This makes the test pass when mock

- None

. You can also try to elevate SkipTest()

, but that might interfere with decorators.

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Inspired by the kind answer (which works) I tried to get it to work without functools

again:

def requires_mock(test):

    def wrapper(*args, **kwargs):
      if mock_not_available:
        raise SkipTest()
      else:
        return test(*args, **kwargs)

    wrapper.__name__ = test.__name__
    return wrapper

Seems to work too. __name__

it is important that nose recognizes the function and flags it when performing complex tests.

I hope I haven't missed anything? Losing faith in you test is a sad thing :(

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