Thread thread = new Thread(scheduler);
thread.setDaemon(true);
thread.start();
// test that it did not run yet...
Thread.currentThread().sleep(70 * 1000); // 70 seconds
scheduler.stop();
// assertEquals(2, validCache.clearCount);
assertTrue("Wrong invocation count: " + validCache.clearCount,
validCache.clearCount == 1 || validCache.clearCount == 2);
assertEquals(0, invalidCache.clearCount);
}