How to execute code only on test failures with python unittest2?

Question

I have some class-based unit tests running in python\'s unittest2 framework. We\'re using Selenium WebDriver, which has a convenient save_screenshot() method. I

Answer 1

Found a solution - I can override failureException:

@property
def failureException(self):
    class MyFailureException(AssertionError):
        def __init__(self_, *args, **kwargs):
            self.b.save_screenshot('%s.png' % self.id())
            return super(MyFailureException, self_).__init__(*args, **kwargs)
    MyFailureException.__name__ = AssertionError.__name__
    return MyFailureException

This seems incredibly hacky but it seems to work so far.