package rx.schedulers;
import rx.Observable;
import rx.Observer;
import rx.Scheduler;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.fail;
final class SchedulerTests {
private SchedulerTests() {
// No instances.
}
/**
* Verifies that the given Scheduler delivers unhandled errors to its executing thread's
* {@link java.lang.Thread.UncaughtExceptionHandler}.
* <p>
* Schedulers which execute on a separate thread from their calling thread should exhibit this behavior. Schedulers
* which execute on their calling thread may not.
*/
static void testUnhandledErrorIsDeliveredToThreadHandler(Scheduler scheduler) throws InterruptedException {
Thread.UncaughtExceptionHandler originalHandler = Thread.getDefaultUncaughtExceptionHandler();
try {
CapturingUncaughtExceptionHandler handler = new CapturingUncaughtExceptionHandler();
Thread.setDefaultUncaughtExceptionHandler(handler);
IllegalStateException error = new IllegalStateException("Should be delivered to handler");
Observable.error(error)
.subscribeOn(scheduler)
.subscribe();
if (!handler.completed.await(3, TimeUnit.SECONDS)) {
fail("timed out");
}
assertEquals("Should have received exactly 1 exception", 1, handler.count);
Throwable cause = handler.caught;
while (cause != null) {
if (error.equals(cause)) break;
if (cause == cause.getCause()) break;
cause = cause.getCause();
}
assertEquals("Our error should have been delivered to the handler", error, cause);
} finally {
Thread.setDefaultUncaughtExceptionHandler(originalHandler);
}
}
/**
* Verifies that the given Scheduler does not deliver handled errors to its executing Thread's
* {@link java.lang.Thread.UncaughtExceptionHandler}.
* <p>
* This is a companion test to {@link #testUnhandledErrorIsDeliveredToThreadHandler}, and is needed only for the
* same Schedulers.
*/
static void testHandledErrorIsNotDeliveredToThreadHandler(Scheduler scheduler) throws InterruptedException {
Thread.UncaughtExceptionHandler originalHandler = Thread.getDefaultUncaughtExceptionHandler();
try {
CapturingUncaughtExceptionHandler handler = new CapturingUncaughtExceptionHandler();
CapturingObserver<Object> observer = new CapturingObserver<Object>();
Thread.setDefaultUncaughtExceptionHandler(handler);
IllegalStateException error = new IllegalStateException("Should be delivered to handler");
Observable.error(error)
.subscribeOn(scheduler)
.subscribe(observer);
if (!observer.completed.await(3, TimeUnit.SECONDS)) {
fail("timed out");
}
assertEquals("Handler should not have received anything", 0, handler.count);
assertEquals("Observer should have received an error", 1, observer.errorCount);
assertEquals("Observer should not have received a next value", 0, observer.nextCount);
Throwable cause = observer.error;
while (cause != null) {
if (error.equals(cause)) break;
if (cause == cause.getCause()) break;
cause = cause.getCause();
}
assertEquals("Our error should have been delivered to the observer", error, cause);
} finally {
Thread.setDefaultUncaughtExceptionHandler(originalHandler);
}
}
private static final class CapturingUncaughtExceptionHandler implements Thread.UncaughtExceptionHandler {
int count = 0;
Throwable caught;
CountDownLatch completed = new CountDownLatch(1);
@Override
public void uncaughtException(Thread t, Throwable e) {
count++;
caught = e;
completed.countDown();
}
}
private static final class CapturingObserver<T> implements Observer<T> {
CountDownLatch completed = new CountDownLatch(1);
int errorCount = 0;
int nextCount = 0;
Throwable error;
@Override
public void onCompleted() {
}
@Override
public void onError(Throwable e) {
errorCount++;
error = e;
completed.countDown();
}
@Override
public void onNext(T t) {
nextCount++;
}
}
}