public void testAccessInnerVariable() throws Exception {
    ZonedDateTime firstTick = clock.time();
    ZonedDateTime verifyFirstTick = clock.lastTick();
    assertEquals(verifyFirstTick, firstTick);

    ZonedDateTime secondTick = clock.time();
    ZonedDateTime verifySecondTick = clock.lastTick();
    assertEquals(verifySecondTick, secondTick);
  }
  public void testVerifyStdDeviation() throws Exception {
    ZonedDateTime firstTick = clock.time();
    ZonedDateTime secondTick = clock.time();
    ZonedDateTime thirdTick = clock.time();
    ZonedDateTime fourthTick = clock.time();

    assertTrue(firstTick.compareTo(secondTick) <= 0);
    assertTrue(secondTick.compareTo(thirdTick) <= 0);
    assertTrue(thirdTick.compareTo(fourthTick) <= 0);
  }