单元测试在调试模式下成功，但是在正常运行时失败

Question

为什么我的单元测试在调试模式下成功，但是在正常运行时失败？

public class ExecutorServiceTest extends MockitoTestCase{   
  private int numThreads;
  private ExecutorService pool;
  private volatile boolean interruptedBitSet;

  @Override
  public void setUp() {
    numThreads = 5;
    pool = Executors.newFixedThreadPool(numThreads);
  }

class TaskChecksForInterruptedBit implements Callable<String> {
    @Override
    public String call() throws Exception {
      interruptedBitSet = false;
      while (!Thread.currentThread().isInterrupted()) {
      }
      interruptedBitSet = Thread.currentThread().isInterrupted();
      return "blah";
    }
  }

public void testCancelSetsInterruptedBitInCallable() throws Exception {
    interruptedBitSet = false;
    final Future<String> future = 
        pool.submit(new TaskChecksForInterruptedBit());
    final boolean wasJustCancelled = future.cancel(true);
    assertTrue(wasJustCancelled);

    // Give time for the thread to notice the interrupted bit and set the flag
    Thread.sleep(5000);

    // This succeeds when stepping through w/ a debugger, but fails when running
    // the test straight. WHY?
    assertTrue(interruptedBitSet);

    assertTrue(future.isDone());
    assertTrue(future.isCancelled());
  }
}

Answer 1

原因几乎可以肯定是，调试器中的断点将暂停主线程，但不暂停任何后台线程-ExecutorService中的那些后台线程。 在Eclipse中调试时，您可以更改断点以暂停所有线程，而不仅仅是主要线程。

当不调试任务提交和立即取消时，是如此之快，以至于您在任务运行一次之前就将其取消。 尝试在这些行之间添加睡眠延迟：

final Future<String> future =  pool.submit(new TaskChecksForInterruptedBit());
Thread.sleep(1000);
final boolean wasJustCancelled = future.cancel(true);

Answer 2

我知道这很旧，但是我遇到了同样的问题。 我的问题是我有一个IEnumerable ，我正在枚举并检查输出。

运行单元测试时， IEnumerable返回的调试顺序与其他顺序不同。 这就是IEnumerable的本质，只需添加一个OrderBy子句即可解决我的问题。

我希望这对外面的人有所帮助，因为这可能会令人沮丧。

Answer 3

您必须确保任务实际开始运行。 它甚至有可能被取消。

public class ExecutorServiceTest {
    private int numThreads;
    private ExecutorService pool;
    private volatile boolean interruptedBitSet;
    private static final CountDownLatch latch = new CountDownLatch(1);

    @Before
    public void setUp() {
        numThreads = 5;
        pool = Executors.newFixedThreadPool(numThreads);
    }

    class TaskChecksForInterruptedBit implements Callable<String> {
        @Override
        public String call() throws Exception {
            interruptedBitSet = false;
            latch.countDown();
            while (!Thread.currentThread().isInterrupted()) {
                System.out.println(System.currentTimeMillis());
            }
            System.out.println("haha");
            interruptedBitSet = Thread.currentThread().isInterrupted();
            return "blah";
        }
    }

    @Test
    public void testCancelSetsInterruptedBitInCallable() throws Exception {
        final Future<String> future =
                pool.submit(new TaskChecksForInterruptedBit());
        interruptedBitSet = false;
        latch.await();
        final boolean wasJustCancelled = future.cancel(true);
        Assert.assertTrue(wasJustCancelled);

        // Give time for the thread to notice the interrupted bit and set the flag
        Thread.sleep(5000);

        // This succeeds when stepping through w/ a debugger, but fails when running
        // the test straight. WHY?
        Assert.assertTrue(interruptedBitSet);

        Assert.assertTrue(future.isDone());
        Assert.assertTrue(future.isCancelled());
    }
}

Answer 4

您应该在终止主线程之前检查所有线程是否都死了

private void shutdownExecutionService(ExecutorService executorService) {
    if (executorService != null) {
        try {
            executorService.shutdown();
            while (!executorService.awaitTermination(10, TimeUnit.HOURS)) {
                logger.info("Awaiting completion of threads.");
            }
        } catch (final InterruptedException e) {
            logger.error("Error while shutting down threadpool", e);
        }
    }
}

Answer 5

通过在线课程进行家庭作业时，我遇到了类似的问题。 我添加到构建路径的课程中的评分器程序使用了JUnit4，我的Eclipse版本将JUnit5添加到了任何新的测试用例中。 我创建了一个新的Java项目，并在没有评分器的情况下为测试用例添加了JUnit5，并将其修复了。 希望这可以帮助。