@Override
    public String toString() {
        return "Entry: " + entry + " exit: " + exit;
    }
@Test
    public void overrideToString() {
        assertEquals(posEquals1.toString(), posEquals2.toString());
        assertNotEquals(posEquals1.toString(), posNotEquals1.toString());
        assertNotEquals(posEquals1.toString(), posNotEquals2.toString());
    }