declarative, readable python testing

puny.py

from functools import wraps

class Equalizer(object):
    def __init__(self, rv):
        self._rv = rv

    def __eq__(self, other):
        assert self._rv == other

class Puny(object):
    def __init__(self, wrapped):
        self._wrapped = wrapped

    def __getattr__(self, name):
        # import pdb; pdb.set_trace()
        attr = getattr(self._wrapped, name)
        if callable(attr):
            @wraps(attr)
            def wrapperfunc(*args, **kwargs):
                return Equalizer(attr(*args, **kwargs))
            return wrapperfunc

        raise AttributeError('%r object has no attribute %s' % (self._wrapped.__class__.__name__, name))


if __name__ == '__main__':
    class ThingToTest(object):
        def return_string(self, rv):
            return rv

    t = Puny(ThingToTest())
    t.return_string('foo') == 'foo'