def METHOD_NAME():
    """
    Should get exactly one per timestep
    """
    model = Model(
        time_step=gs.hours(1),
        start_time='2022-12-10T00:00',
        duration=gs.hours(12),
    )
    model.outputters += MemoryOutputter()
    model.spills += surface_point_line_spill(
        num_elements=10,
        start_position=(0, 0, 0),
        release_time=model.start_time,
        end_release_time=model.start_time + 10 * gs.seconds(model.time_step),
        )
    model.full_run()
    results = model.outputters[0]
    data = results.data_buffer.certain
    # there should be 0 of the Elements at time zero
    # then one per timestep
    for i in range(11):
        assert len(data[i]['mass']) == i
    for i in range(11, 13):
        assert len(data[i]['mass']) == 10