@Test
public void traverseBarelyWorks() {

    EquivalenceFinder<Integer> finder = create(6);
    finder.markEquivalent(1, 2);
    finder.markEquivalent(2, 3);
    finder.markEquivalent(3, 4);
    finder.markEquivalent(4, 5);
    finder.markEquivalent(5, 6);
    check(finder, true, 1, 6);
}