Permuterator Test

PermuteratorTest.java

public class PermuteratorTest {

    private Permuterator permuterator;
    private Permuterator.Validator validator;

    @Before
    public void setUp() throws Exception {
        permuterator = new Permuterator();
        validator = mock(Permuterator.Validator.class);
    }

    @Test
    public void permute() throws Exception {
        permuterator.permute(Arrays.asList("A", "B", "C"), 4, validator);
        verify(validator, times(81)).validatePermutation(any());
    }
}