單元測試在調試模式下成功，但是在正常運行時失敗

Question

為什么我的單元測試在調試模式下成功，但是在正常運行時失敗？

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

原因幾乎可以肯定是，調試器中的斷點將暫停主線程，但不暫停任何后台線程-ExecutorService中的那些后台線程。 在Eclipse中調試時，您可以更改斷點以暫停所有線程，而不僅僅是主要線程。

當不調試任務提交和立即取消時，是如此之快，以至於您在任務運行一次之前就將其取消。 嘗試在這些行之間添加睡眠延遲：

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

Answer 2

我知道這很舊，但是我遇到了同樣的問題。 我的問題是我有一個IEnumerable ，我正在枚舉並檢查輸出。

運行單元測試時， IEnumerable返回的調試順序與其他順序不同。 這就是IEnumerable的本質，只需添加一個OrderBy子句即可解決我的問題。

我希望這對外面的人有所幫助，因為這可能會令人沮喪。

Answer 3

您必須確保任務實際開始運行。 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

您應該在終止主線程之前檢查所有線程是否都死了

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

通過在線課程進行家庭作業時，我遇到了類似的問題。 我添加到構建路徑的課程中的評分器程序使用了JUnit4，我的Eclipse版本將JUnit5添加到了任何新的測試用例中。 我創建了一個新的Java項目，並在沒有評分器的情況下為測試用例添加了JUnit5，並將其修復了。 希望這可以幫助。