RegularTimePeriod p1 = new Day();
        RegularTimePeriod p2 = p1.next();
        s1.add(p1, 100.0);
        s1.add(p2, 200.0);
        boolean b3 = s1.equals(s2);
        assertFalse("b3", b3);

        s2.add(p1, 100.0);
        s2.add(p2, 200.0);
        boolean b4 = s1.equals(s2);
        assertTrue("b4", b4);