def test_inverse_x(self, num_ctrl_qubits):
"""Test inverting the controlled X gate."""
cnx = XGate().control(num_ctrl_qubits)
inv_cnx = cnx.inverse()
result = Operator(cnx).compose(Operator(inv_cnx))
np.testing.assert_array_almost_equal(result.data,
np.identity(result.dim[0]))
