try:
    from nose.plugins.skip import SkipTest
except ImportError:
    try:
        from unittest.case import SkipTest  # Python >= 2.7
    except ImportError:
        try:
            from unittest2.case import SkipTest  # Python < 2.7
        except ImportError:

            class SkipTest(Exception):
                """Raise this exception to mark a test as skipped.
                """

                pass


try:
    from nose.tools import assert_equal, assert_in, assert_raises


except ImportError:

    def assert_equal(expected, result):
        print("Expected:\n%s\n" % expected)
        print("Got:\n%s\n" % result)
        assert expected == result

    def assert_in(result, expected_set):
        nums = range(1, len(expected_set) + 1)
        for i, expected in zip(nums, expected_set):
            print("Expected %d:\n%s\n" % (i, expected))
        print("Got:\n%s\n" % result)
        assert result in expected_set

    class assert_raises(object):
        def __init__(self, exception_type):
            self.watch_exception_type = exception_type

        def __enter__(self):
            pass

        def __exit__(self, exception_type, exception_value, traceback):
            if isinstance(exception_value, self.watch_exception_type):
                return True  # suppress exception
            elif exception_type is None:
                msg = "%s not raised" % self.watch_exception_type.__name__
                raise AssertionError(msg)
            # otherwise propagate whatever other exception is raised