test_ssl.py 文件源码

def test_old_callback_forgotten(self):
        """
        If :py:obj:`Context.set_tlsext_servername_callback` is used to specify a new
        callback, the one it replaces is dereferenced.
        """
        def callback(connection):
            pass

        def replacement(connection):
            pass

        context = Context(TLSv1_METHOD)
        context.set_tlsext_servername_callback(callback)

        tracker = ref(callback)
        del callback

        context.set_tlsext_servername_callback(replacement)

        # One run of the garbage collector happens to work on CPython.  PyPy
        # doesn't collect the underlying object until a second run for whatever
        # reason.  That's fine, it still demonstrates our code has properly
        # dropped the reference.
        collect()
        collect()

        callback = tracker()
        if callback is not None:
            referrers = get_referrers(callback)
            if len(referrers) > 1:
                self.fail("Some references remain: %r" % (referrers,))