}
                r.run();
              }
            });
    Runnable task = numCalls::incrementAndGet;
    assertThrows(RejectedExecutionException.class, () -> executor.execute(task));
    assertEquals(0, numCalls.get());
    reject.set(false);
    executor.execute(task);
    assertEquals(1, numCalls.get());
  }

  /*
   * Under Android, MyError propagates up and fails the test?

    public <T> Future<T> submit(Callable<T> task) {
      lastMethodCalled = "submit";
      assertThat(task).isInstanceOf(WrappedCallable.class);
      return inline.submit(task);
    }

    @Override
    public Future<?> submit(Runnable task) {
      lastMethodCalled = "submit";
      assertThat(task).isInstanceOf(WrappedRunnable.class);
      return inline.submit(task);
    }

    @Override

  private volatile boolean taskDone;

  public void testNoOpScheduledExecutor() throws InterruptedException {
    taskDone = false;
    Runnable task = () -> taskDone = true;
    ScheduledFuture<?> future =
        TestingExecutors.noOpScheduledExecutor().schedule(task, 10, MILLISECONDS);
    Thread.sleep(20);
    assertFalse(taskDone);
    assertFalse(future.isDone());
  }

  private volatile boolean taskDone;

  public void testNoOpScheduledExecutor() throws InterruptedException {
    taskDone = false;
    Runnable task = () -> taskDone = true;
    ScheduledFuture<?> future =
        TestingExecutors.noOpScheduledExecutor().schedule(task, 10, MILLISECONDS);
    Thread.sleep(20);
    assertFalse(taskDone);
    assertFalse(future.isDone());
  }

  // Regression test for a deadlock where a task could be stuck busy waiting for the task to
  // transition to DONE
  public void testInterruptThrows() throws Exception {
    CountDownLatch isInterruptibleRegistered = new CountDownLatch(1);
    SettableFuture<String> taskResult = SettableFuture.create();
    InterruptibleTask<String> task =
        new InterruptibleTask<String>() {
          @Override

  // Regression test for a deadlock where a task could be stuck busy waiting for the task to
  // transition to DONE
  public void testInterruptThrows() throws Exception {
    CountDownLatch isInterruptibleRegistered = new CountDownLatch(1);
    SettableFuture<String> taskResult = SettableFuture.create();
    InterruptibleTask<String> task =
        new InterruptibleTask<String>() {
          @Override

            "resolveAllDependencies",
        ) -> true

        task.name.endsWith("Wrapper") -> true
        task.name in listOf("docs", "stageDocs", "serveDocs") -> true
        task.name.startsWith("userguide") -> true
        task.name == "samplesMultiPage" -> true
        task.typeSimpleName() in listOf(
            "JavaExecProjectGeneratorTask",
            "NativeProjectWithDepsGeneratorTask",
            "PerformanceTest",

    assertFalse(task.isDone());
    assertFalse(task.isCancelled());

    // Start the task to put it in the RUNNING state.  Have to use a separate
    // thread because the task will block on the task latch after unblocking
    // the run latch.
    exec.execute(task);
    runLatch.await();
    assertEquals(1, listenerLatch.getCount());
    assertFalse(task.isDone());
    assertFalse(task.isCancelled());

## Create a task function { #create-a-task-function }

Create a function to be run as the background task.

It is just a standard function that can receive parameters.

It can be an `async def` or normal `def` function, **FastAPI** will know how to handle it correctly.

In this case, the task function will write to a file (simulating sending an email).

        tasks.withType(AsciidoctorTask.class).configureEach(task -> {
            if (task.getName().equals("asciidoctor")) {
                // ignore this task
                task.setEnabled(false);
                return;
            }

            task.setExecutionMode(ExecutionMode.OUT_OF_PROCESS);
            task.outputOptions(options -> {
                options.setSeparateOutputDirs(false);