### Question:
Stopwatch implements TestRule { protected void succeeded(long nanos, Description description) { } Stopwatch();   Stopwatch(Clock clock); long runtime(TimeUnit unit); final Statement apply(Statement base, Description description);  }### Answer:
@Test public void succeeded() { Result result = runTest(SuccessfulTest.class); assertEquals(0, result.getFailureCount()); assertThat(record.name, is("successfulTest")); assertThat(record.name, is(finishedRecord.name)); assertThat(record.status, is(TestStatus.SUCCEEDED)); assertTrue("timeSpent > 0", record.duration > 0); assertThat(record.duration, is(finishedRecord.duration)); }