def METHOD_NAME(caplog):
    """
    Attempting phase_flip without CTFFilters should warn.
    """
    # this test doesn't depend on dtype, not parametrized
    # Create a Simulation without any CTFFilters
    sim = Simulation(
        L=8,
        n=num_images,
        dtype=np.float32,
    )
    # assert we log a warning to the user
    with caplog.at_level(logging.WARNING):
        _ = sim.phase_flip()
        assert "No Filters found" in caplog.text