"""Implementations of unittest features from the future."""

# Use unittest2 if it's available, otherwise unittest.  This gives us
# back-ported features for 2.6.
try:
    import unittest2 as unittest
except ImportError:
    import unittest


def unittest_has(method):
    """Does `unittest.TestCase` have `method` defined?"""
    return hasattr(unittest.TestCase, method)


class TestCase(unittest.TestCase):
    """Just like unittest.TestCase, but with assert methods added.

    Designed to be compatible with 3.1 unittest.  Methods are only defined if
    `unittest` doesn't have them.

    """
    # pylint: disable=missing-docstring

    if not unittest_has('assertCountEqual'):
        def assertCountEqual(self, s1, s2):
            """Assert these have the same elements, regardless of order."""
            self.assertEqual(set(s1), set(s2))

    if not unittest_has('assertRaisesRegex'):
        def assertRaisesRegex(self, *args, **kwargs):
            return self.assertRaisesRegexp(*args, **kwargs)

    if not unittest_has('assertRegex'):
        def assertRegex(self, *args, **kwargs):
            return self.assertRegexpMatches(*args, **kwargs)