def METHOD_NAME(self):
    """Test that the ordering is consistent with quantum_info's Operator."""
    with self.subTest(msg="simple, single register example"):
        x = QuantumCircuit(1)
        x.x(0)
        i = QuantumCircuit(1)
        circuit = x.tensor(i)
        operator = Operator(x).tensor(Operator(i))
        self.assertEqual(Operator(circuit), operator)
    with self.subTest(msg="multi register example"):
        qrs = [QuantumRegister(1) for _ in range(6)]
        top = QuantumCircuit(*qrs[:4])
        top.h(0)
        top.x(1)
        top.h(1)
        top.ccx(0, 1, 3)
        top.cry(-1.2, 3, 2)
        bottom = QuantumCircuit(*qrs[4:])
        bottom.sx(0)
        bottom.p(3.01, 0)
        bottom.cx(0, 1)
        circuit = bottom.tensor(top)
        operator = Operator(bottom).tensor(Operator(top))
        self.assertEqual(Operator(circuit), operator)
    with self.subTest(msg="nested circuits"):
        sub = QuantumCircuit(3)
        sub.h(0)
        sub.swap(0, 1)
        sub.cx(1, 2)
        sub.cx(2, 0)
        larger = QuantumCircuit(4)
        larger.h(range(3))
        larger.append(sub.to_instruction(), [3, 2, 1])
        larger.append(sub.control(), [0, 1, 2, 3])
        circuit = larger.tensor(larger)
        operator = Operator(larger).tensor(Operator(larger))
        self.assertEqual(Operator(circuit), operator)