def METHOD_NAME(empty_model, cont_spill):
    """
    Model starts one timestep before the spill
    """
    model = empty_model
    model.start_time = model.start_time - TIME_STEP
    model.spills += cont_spill
    model.full_run()
    results = model.outputters[0]
    data = results.data_buffer.certain
    # there should be 100 Elements at all times
    # there should be 0 Elements at time zero
    assert len(data[0]['mass']) == 0
    assert len(data[1]['mass']) == 0
    assert len(data[2]['mass']) == NUM_ELEMENTS / 4 * 1
    assert len(data[3]['mass']) == NUM_ELEMENTS / 4 * 2
    assert len(data[4]['mass']) == NUM_ELEMENTS / 4 * 3
    assert len(data[5]['mass']) == NUM_ELEMENTS