def assertContains(self, haystack, needle):
        """Assert that `needle` is contained within `haystack`."""
        assert needle in haystack, '\n'.join((
            'Text not found within bigger block of text.\n',
            'Needle:',
            needle,
            '\nHaystack:',
            haystack,
        ))
dataset/ETHPy150Open lukesneeringer/django-pgfields/tests/composite/tests.py/CreateTypeSuite.assertContains/original