CancelTaskFromJavaExecutor.java

@Test
	public void cancel_task() throws InterruptedException {
		LocalDateTime start = LocalDateTime.now();
		Action action = () -> {
			try {
				Thread.sleep(1000);
			} catch (InterruptedException ignored) {

			}
		};
		Scheduler scheduler = Schedulers.from(Executors.newSingleThreadExecutor());
		TestObserver<Void> test = Completable.fromAction(action).subscribeOn(scheduler).test();

		Thread.sleep(50);
		test.dispose();
		test.assertNoErrors();
		assertThat(start.plus(500, ChronoUnit.MILLIS).isAfter(LocalDateTime.now()), CoreMatchers.is(true));
	}