Class TestFailingIter

Lib/test/test_functools.py:1079–1081

        self.assertRaises(TypeError, self.reduce, add, object())

        class TestFailingIter:
            def __iter__(self):
                raise RuntimeError
        self.assertRaises(RuntimeError, self.reduce, add, TestFailingIter())

        self.assertEqual(self.reduce(add, [], None), None)