def test_wide_python_build():
    """This test is meant to fail on narrow python builds (common on Mac OS X).

    See https://github.com/RDFLib/rdflib/issues/456 for more information.
    """
    assert len("\U0010FFFF") == 1, (
        "You are using a narrow Python build!\n"
        "This means that your Python does not properly support chars > 16bit.\n"
        'On your system chars like c=u"\\U0010FFFF" will have a len(c)==2.\n'
        "As this can cause hard to debug problems with string processing\n"
        "(slicing, regexp, ...) later on, we strongly advise to use a wide\n"
        "Python build in production systems."
    )