[kiwidude]

What I have done on my local version is put prints statements inside the test functions like this:

def isbn_test(isbn):
    isbn_ = check_isbn(isbn)

    def test(mi):
        misbn = check_isbn(mi.isbn)
        if misbn and misbn == isbn_:
            return True
        prints('ISBN test failed. Expected: %s found %s'%(isbn_, misbn))
        return False

    return test