Stamp implements Serializable { public boolean leq(Stamp other) { return event.leq(other.event); } Stamp();   Stamp(ID id, Event event); Stamp[] fork(); Stamp[] peek(); Stamp join(Stamp other); Stamp event(); @Override String toString(); @Override boolean equals(Object o); @Override int hashCode(); Stamp[] send(); Stamp receive(Stamp other); Stamp[] sync(Stamp other); boolean leq(Stamp other);  }
@Test public void testLeq() { Stamp s1 = new Stamp(); Stamp s2 = new Stamp(); Assert.assertTrue(s1.leq(s2.event())); Assert.assertTrue(Causality.lessThanEquals(s1, s2.event())); Assert.assertFalse(s2.event().leq(s1)); Assert.assertFalse(Causality.lessThanEquals(s2.event(), s1)); }