@Test
    public void insertLastHandlesTailCorrectly() {
        l.insertLast(a);
        for (int i = 1; i < 10; i++) {
            l.insertLast(new Vertex(i));
        }
        int i = 0;
        Vertex test = l.min();
        while (test != null) {
            test = l.succ(test);
            i++;
            if (i > 300) {
                break;
            }
        }
        assertTrue("Endless loop!", i < 300);
    }