public static long currentTimeMillis() {
        return CLOCK.currentTimeMillis();
    }
@Test
    public void testSystemOffsetClock() {
        Clock.SystemOffsetClock clock = new Clock.SystemOffsetClock(-999999999);

        long systemMillis = System.currentTimeMillis();
        sleepSeconds(1);
        long offsetMillis = clock.currentTimeMillis();
        assertTrue(format("SystemOffsetClock should be far behind the normal clock! %d < %d", offsetMillis, systemMillis),
                offsetMillis < systemMillis);
    }