def METHOD_NAME(backend):
    """Check controlled_by SWAP that should not be applied."""
    initial_rho = np.zeros((16, 16))
    initial_rho[0, 0] = 1
    c = Circuit(4, density_matrix=True)
    c.add(gates.X(0))
    c.add(gates.SWAP(1, 3).controlled_by(0, 2))
    final_rho = backend.execute_circuit(c, np.copy(initial_rho))
    c = Circuit(4, density_matrix=True)
    c.add(gates.X(0))
    target_rho = backend.execute_circuit(c, np.copy(initial_rho))
    backend.assert_allclose(final_rho, target_rho)