def test_propagate_flipped(self):
        class InterfaceWithFlippedSub(Component):
            signature = Signature({
                "a": In(Signature({
                    "b": Out(Signature({
                        "c": Out(1)
                    })),
                    "d": In(Signature({
                        "e": Out(1)
                    })),
                    "f": Out(1)
                }))
            })

            def __init__(self):
                super().__init__()
                self.g = Signature({"h": Out(1)})

        ifsub = InterfaceWithFlippedSub()
        self.assertIsInstance(ifsub.a.b.signature, FlippedSignature)
        self.assertIsInstance(ifsub.a.d.signature, Signature)
        self.assertIsInstance(ifsub.signature.members["a"].signature.
                              members["b"].signature, FlippedSignature)
        self.assertIsInstance(ifsub.signature.members["a"].signature.
                              members["d"].signature, Signature)
        self.assertEqual(ifsub.a.signature.members["f"].flow, In)
        self.assertEqual(ifsub.g.members["h"].flow, Out)