testing.py

import contextlib
import functools
import inspect

import pytest


def for_each(examples):

    def decorator(fun):
        args, vargs, kwargs, defaults = inspect.getargspec(fun)
        if vargs or kwargs or defaults:
            raise TypeError('\n  '.join([
                'Unsupported signature: '.format(fun),
                'args = {}'.format(args),
                'vargs = {}'.format(vargs),
                'kwargs = {}'.format(kwargs),
                'defaults = {}'.format(defaults),
            ]))
        argnames = ','.join(args)
        return pytest.mark.parametrize(argnames, examples)(fun)

    return decorator


def for_each_kwargs(examples):

    def decorator(fun):
        args, vargs, kwargs, defaults = inspect.getargspec(fun)
        if vargs or kwargs:
            raise TypeError('\n  '.join([
                'Unsupported signature: '.format(fun),
                'args = {}'.format(args),
                'vargs = {}'.format(vargs),
                'kwargs = {}'.format(kwargs),
                'defaults = {}'.format(defaults),
            ]))

        # FIXME This wrapper pollutes the test log.
        @functools.wraps(fun)
        def wrapped_fun(example):
            example = {k: v for k, v in example.iteritems() if k in args}
            return fun(**example)

        return pytest.mark.parametrize('example', examples)(wrapped_fun)

    return decorator


@contextlib.contextmanager
def xfail_if_not_implemented():
    try:
        yield
    except NotImplementedError as e:
        pytest.xfail(reason=str(e))


@contextlib.contextmanager
def skip_if_not_implemented():
    try:
        yield
    except NotImplementedError as e:
        pytest.skip(str(e))