@Test
public void testObserveOnWithSlowConsumer() {
int NUM = (int) (Observable.bufferSize() * 0.2);
AtomicInteger c = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<>();
incrementingIntegers(c)
.observeOn(Schedulers.computation())
.map(
i -> {
try {
Thread.sleep(1);
} catch (InterruptedException e) {
e.printStackTrace();
}
return i;
})
.take(NUM)
.subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println(
"testObserveOnWithSlowConsumer => Received: " + ts.valueCount() + " Emitted: " + c.get());
assertEquals(NUM, ts.valueCount());
assertTrue(c.get() < Observable.bufferSize() * 2);
}
@Test
public void testTakeFilterSkipChainAsync() {
int NUM = (int) (Observable.bufferSize() * 2.1);
AtomicInteger c = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<>();
incrementingIntegers(c)
.observeOn(Schedulers.computation())
.skip(10000)
.filter(i -> i > 11000)
.take(NUM)
.subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
// emit 10000 that are skipped
// emit next 1000 that are filtered out
// take NUM
// so emitted is at least 10000+1000+NUM + extra for buffer size/threshold
int expected = 10000 + 1000 + Observable.bufferSize() * 3 + Observable.bufferSize() / 2;
System.out.println(
"testTakeFilterSkipChain => Received: "
+ ts.valueCount()
+ " Emitted: "
+ c.get()
+ " Expected: "
+ expected);
assertEquals(NUM, ts.valueCount());
assertTrue(c.get() < expected);
}
@Test
public void testZipAsync() {
int NUM = (int) (Observable.bufferSize() * 2.1);
AtomicInteger c1 = new AtomicInteger();
AtomicInteger c2 = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<>();
Observable<Integer> zipped =
Observable.zip(
incrementingIntegers(c1).subscribeOn(Schedulers.computation()),
incrementingIntegers(c2).subscribeOn(Schedulers.computation()),
(t1, t2) -> t1 + t2);
zipped.take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println(
"testZipAsync => Received: "
+ ts.valueCount()
+ " Emitted: "
+ c1.get()
+ " / "
+ c2.get());
assertEquals(NUM, ts.valueCount());
int max = Observable.bufferSize() * 5;
assertTrue("" + c1.get() + " >= " + max, c1.get() < max);
assertTrue("" + c2.get() + " >= " + max, c2.get() < max);
}
@Test
@Ignore // the test is non-deterministic and can't be made deterministic
public void testFlatMapAsync() {
int NUM = (int) (Observable.bufferSize() * 2.1);
AtomicInteger c = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<>();
incrementingIntegers(c)
.subscribeOn(Schedulers.computation())
.flatMap(
i ->
incrementingIntegers(new AtomicInteger())
.take(10)
.subscribeOn(Schedulers.computation()))
.take(NUM)
.subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println(
"testFlatMapAsync => Received: "
+ ts.valueCount()
+ " Emitted: "
+ c.get()
+ " Size: "
+ Observable.bufferSize());
assertEquals(NUM, ts.valueCount());
// even though we only need 10, it will request at least Observable.bufferSize(), and then as it
// drains keep requesting more
// and then it will be non-deterministic when the take() causes the unsubscribe as it is
// scheduled on 10 different schedulers (threads)
// normally this number is ~250 but can get up to ~1200 when Observable.bufferSize() == 1024
assertTrue(c.get() <= Observable.bufferSize() * 2);
}
@Test
public void testMergeAsyncThenObserveOnLoop() {
for (int i = 0; i < 500; i++) {
if (i % 10 == 0) {
System.out.println("testMergeAsyncThenObserveOnLoop >> " + i);
}
// Verify there is no MissingBackpressureException
int NUM = (int) (Observable.bufferSize() * 4.1);
AtomicInteger c1 = new AtomicInteger();
AtomicInteger c2 = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<>();
Observable<Integer> merged =
Observable.merge(
incrementingIntegers(c1).subscribeOn(Schedulers.computation()),
incrementingIntegers(c2).subscribeOn(Schedulers.computation()));
merged.observeOn(Schedulers.io()).take(NUM).subscribe(ts);
ts.awaitTerminalEvent(5, TimeUnit.SECONDS);
ts.assertComplete();
ts.assertNoErrors();
System.out.println(
"testMergeAsyncThenObserveOn => Received: "
+ ts.valueCount()
+ " Emitted: "
+ c1.get()
+ " / "
+ c2.get());
assertEquals(NUM, ts.valueCount());
}
}
@Test
public void testMergeAsync() {
int NUM = (int) (Observable.bufferSize() * 4.1);
AtomicInteger c1 = new AtomicInteger();
AtomicInteger c2 = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<>();
Observable<Integer> merged =
Observable.merge(
incrementingIntegers(c1).subscribeOn(Schedulers.computation()),
incrementingIntegers(c2).subscribeOn(Schedulers.computation()));
merged.take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println(
"testMergeAsync => Received: "
+ ts.valueCount()
+ " Emitted: "
+ c1.get()
+ " / "
+ c2.get());
assertEquals(NUM, ts.valueCount());
// either one can starve the other, but neither should be capable of doing more than 5 batches
// (taking 4.1)
// TODO is it possible to make this deterministic rather than one possibly starving the other?
// benjchristensen => In general I'd say it's not worth trying to make it so, as "fair"
// algoritms generally take a performance hit
int max = Observable.bufferSize() * 7;
assertTrue("" + c1.get() + " >= " + max, c1.get() < max);
assertTrue("" + c2.get() + " >= " + max, c2.get() < max);
}
@Test
public void testObserveOn() {
int NUM = (int) (Observable.bufferSize() * 2.1);
AtomicInteger c = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<>();
incrementingIntegers(c).observeOn(Schedulers.computation()).take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println("testObserveOn => Received: " + ts.valueCount() + " Emitted: " + c.get());
assertEquals(NUM, ts.valueCount());
assertTrue(c.get() < Observable.bufferSize() * 4);
}
/**
* Incrementing int without backpressure.
*
* @param counter
* @return
*/
private static Observable<Integer> firehose(final AtomicInteger counter) {
return Observable.create(
s -> {
Subscription s2 = new FirehoseNoBackpressure(counter, s);
s.onSubscribe(s2);
});
}
@Test(timeout = 10000)
public void testOnBackpressureDropSynchronous() {
for (int i = 0; i < 100; i++) {
int NUM =
(int) (Observable.bufferSize() * 1.1); // > 1 so that take doesn't prevent buffer overflow
AtomicInteger c = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<>();
firehose(c).onBackpressureDrop().map(SLOW_PASS_THRU).take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
List<Integer> onNextEvents = ts.values();
assertEquals(NUM, onNextEvents.size());
Integer lastEvent = onNextEvents.get(NUM - 1);
System.out.println(
"testOnBackpressureDrop => Received: "
+ onNextEvents.size()
+ " Emitted: "
+ c.get()
+ " Last value: "
+ lastEvent);
// it drop, so we should get some number far higher than what would have sequentially
// incremented
assertTrue(NUM - 1 <= lastEvent.intValue());
}
}
@Test
public void testFlatMapSync() {
int NUM = (int) (Observable.bufferSize() * 2.1);
AtomicInteger c = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<>();
incrementingIntegers(c)
.flatMap(i -> incrementingIntegers(new AtomicInteger()).take(10))
.take(NUM)
.subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println("testFlatMapSync => Received: " + ts.valueCount() + " Emitted: " + c.get());
assertEquals(NUM, ts.valueCount());
// expect less than 1 buffer since the flatMap is emitting 10 each time, so it is NUM/10 that
// will be taken.
assertTrue(c.get() < Observable.bufferSize());
}
@Test
public void testMergeAsyncThenObserveOn() {
int NUM = (int) (Observable.bufferSize() * 4.1);
AtomicInteger c1 = new AtomicInteger();
AtomicInteger c2 = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<>();
Observable<Integer> merged =
Observable.merge(
incrementingIntegers(c1).subscribeOn(Schedulers.computation()),
incrementingIntegers(c2).subscribeOn(Schedulers.computation()));
merged.observeOn(Schedulers.newThread()).take(NUM).subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println(
"testMergeAsyncThenObserveOn => Received: "
+ ts.valueCount()
+ " Emitted: "
+ c1.get()
+ " / "
+ c2.get());
assertEquals(NUM, ts.valueCount());
// either one can starve the other, but neither should be capable of doing more than 5 batches
// (taking 4.1)
// TODO is it possible to make this deterministic rather than one possibly starving the other?
// benjchristensen => In general I'd say it's not worth trying to make it so, as "fair"
// algoritms generally take a performance hit
// akarnokd => run this in a loop over 10k times and never saw values get as high as 7*SIZE, but
// since observeOn delays the unsubscription non-deterministically, the test will remain
// unreliable
assertTrue(c1.get() < Observable.bufferSize() * 7);
assertTrue(c2.get() < Observable.bufferSize() * 7);
}
@Test
public void testSubscribeOnScheduling() {
// in a loop for repeating the concurrency in this to increase chance of failure
for (int i = 0; i < 100; i++) {
int NUM = (int) (Observable.bufferSize() * 2.1);
AtomicInteger c = new AtomicInteger();
ConcurrentLinkedQueue<Thread> threads = new ConcurrentLinkedQueue<>();
TestSubscriber<Integer> ts = new TestSubscriber<>();
// observeOn is there to make it async and need backpressure
incrementingIntegers(c, threads)
.subscribeOn(Schedulers.computation())
.observeOn(Schedulers.computation())
.take(NUM)
.subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println(
"testSubscribeOnScheduling => Received: " + ts.valueCount() + " Emitted: " + c.get());
assertEquals(NUM, ts.valueCount());
assertTrue(c.get() < Observable.bufferSize() * 4);
Thread first = null;
for (Thread t : threads) {
System.out.println("testSubscribeOnScheduling => thread: " + t);
if (first == null) {
first = t;
} else {
if (!first.equals(t)) {
fail("Expected to see the same thread");
}
}
}
System.out.println(
"testSubscribeOnScheduling => Number of batch requests seen: " + threads.size());
assertTrue(threads.size() > 1);
System.out.println(
"-------------------------------------------------------------------------------------------");
}
}
@Test(timeout = 20000)
public void testOnBackpressureDropWithAction() {
for (int i = 0; i < 100; i++) {
final AtomicInteger emitCount = new AtomicInteger();
final AtomicInteger dropCount = new AtomicInteger();
final AtomicInteger passCount = new AtomicInteger();
final int NUM =
Observable.bufferSize() * 3; // > 1 so that take doesn't prevent buffer overflow
TestSubscriber<Integer> ts = new TestSubscriber<>();
firehose(emitCount)
.onBackpressureDrop(v -> dropCount.incrementAndGet())
.doOnNext(v -> passCount.incrementAndGet())
.observeOn(Schedulers.computation())
.map(SLOW_PASS_THRU)
.take(NUM)
.subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
List<Integer> onNextEvents = ts.values();
Integer lastEvent = onNextEvents.get(NUM - 1);
System.out.println(
testName.getMethodName()
+ " => Received: "
+ onNextEvents.size()
+ " Passed: "
+ passCount.get()
+ " Dropped: "
+ dropCount.get()
+ " Emitted: "
+ emitCount.get()
+ " Last value: "
+ lastEvent);
assertEquals(NUM, onNextEvents.size());
// in reality, NUM < passCount
assertTrue(NUM <= passCount.get());
// it drop, so we should get some number far higher than what would have sequentially
// incremented
assertTrue(NUM - 1 <= lastEvent.intValue());
assertTrue(0 < dropCount.get());
assertEquals(emitCount.get(), passCount.get() + dropCount.get());
}
}
private static Observable<Integer> incrementingIntegers(
final AtomicInteger counter, final ConcurrentLinkedQueue<Thread> threadsSeen) {
return Observable.create(
new Publisher<Integer>() {
@Override
public void subscribe(final Subscriber<? super Integer> s) {
s.onSubscribe(
new Subscription() {
int i = 0;
volatile boolean cancelled;
final AtomicLong requested = new AtomicLong();
@Override
public void request(long n) {
if (SubscriptionHelper.validateRequest(n)) {
return;
}
if (threadsSeen != null) {
threadsSeen.offer(Thread.currentThread());
}
long _c = BackpressureHelper.add(requested, n);
if (_c == 0) {
while (!cancelled) {
counter.incrementAndGet();
s.onNext(i++);
if (requested.decrementAndGet() == 0) {
// we're done emitting the number requested so return
return;
}
}
}
}
@Override
public void cancel() {
cancelled = true;
}
});
}
});
}
@Test(timeout = 10000)
public void testOnBackpressureDrop() {
long t = System.currentTimeMillis();
for (int i = 0; i < 100; i++) {
// stop the test if we are getting close to the timeout because slow machines
// may not get through 100 iterations
if (System.currentTimeMillis() - t > TimeUnit.SECONDS.toMillis(9)) {
break;
}
int NUM =
(int) (Observable.bufferSize() * 1.1); // > 1 so that take doesn't prevent buffer overflow
AtomicInteger c = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<>();
firehose(c)
.onBackpressureDrop()
.observeOn(Schedulers.computation())
.map(SLOW_PASS_THRU)
.take(NUM)
.subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
List<Integer> onNextEvents = ts.values();
assertEquals(NUM, onNextEvents.size());
Integer lastEvent = onNextEvents.get(NUM - 1);
System.out.println(
"testOnBackpressureDrop => Received: "
+ onNextEvents.size()
+ " Emitted: "
+ c.get()
+ " Last value: "
+ lastEvent);
// it drop, so we should get some number far higher than what would have sequentially
// incremented
assertTrue(NUM - 1 <= lastEvent.intValue());
}
}
@Test(timeout = 2000)
public void testOnBackpressureBuffer() {
int NUM =
(int) (Observable.bufferSize() * 1.1); // > 1 so that take doesn't prevent buffer overflow
AtomicInteger c = new AtomicInteger();
TestSubscriber<Integer> ts = new TestSubscriber<>();
firehose(c)
.takeWhile(t1 -> t1 < 100000)
.onBackpressureBuffer()
.observeOn(Schedulers.computation())
.map(SLOW_PASS_THRU)
.take(NUM)
.subscribe(ts);
ts.awaitTerminalEvent();
ts.assertNoErrors();
System.out.println(
"testOnBackpressureBuffer => Received: " + ts.valueCount() + " Emitted: " + c.get());
assertEquals(NUM, ts.valueCount());
// it buffers, so we should get the right value sequentially
assertEquals(NUM - 1, ts.values().get(NUM - 1).intValue());
}