@Test
public void shouldRemoveDebts() throws Exception {

    final Debt debt = debt(thomas, amount(10), matthias);
    final Remove combinationResult = new Remove(debt);
    final List<Debt> list = new ArrayList<>(Arrays.asList(debt));
    combinationResult.applyTo(list);
    assertThat(list, allOf(
            iterableWithSize(0),
            not(hasItem(debt))
    ));
}