test_errors.py 文件源码

def test_element_cyclic_gc_none(self):
        # test if cyclic reference can crash etree
        Element = self.etree.Element

        # must disable tracing as it could change the refcounts
        trace_func = sys.gettrace()
        try:
            sys.settrace(None)
            gc.collect()

            count = sys.getrefcount(None)

            l = [Element('name'), Element('name')]
            l.append(l)

            del l
            gc.collect()

            self.assertEqual(sys.getrefcount(None), count)
        finally:
            sys.settrace(trace_func)