@Test public void testMembership() throws Exception {
IntervalSet s = IntervalSet.of(15,15);
s.add(50,60);
assertTrue(!s.member(0));
assertTrue(!s.member(20));
assertTrue(!s.member(100));
assertTrue(s.member(15));
assertTrue(s.member(55));
assertTrue(s.member(50));
assertTrue(s.member(60));