rx.observers.TestSubscriber Maven / Gradle / Ivy
/**
* Copyright 2014 Netflix, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package rx.observers;
import java.util.List;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import rx.Notification;
import rx.Observer;
import rx.Subscriber;
/**
* A {@code TestSubscriber} is a variety of {@link Subscriber} that you can use for unit testing, to perform
* assertions, inspect received events, or wrap a mocked {@code Subscriber}.
*/
public class TestSubscriber extends Subscriber {
private final TestObserver testObserver;
private final CountDownLatch latch = new CountDownLatch(1);
private volatile Thread lastSeenThread;
public TestSubscriber(Subscriber delegate) {
this.testObserver = new TestObserver(delegate);
}
public TestSubscriber(Observer delegate) {
this.testObserver = new TestObserver(delegate);
}
public TestSubscriber() {
this.testObserver = new TestObserver(new Observer() {
@Override
public void onCompleted() {
// do nothing
}
@Override
public void onError(Throwable e) {
// do nothing
}
@Override
public void onNext(T t) {
// do nothing
}
});
}
/**
* Notifies the Subscriber that the {@code Observable} has finished sending push-based notifications.
*
* The {@code Observable} will not call this method if it calls {@link #onError}.
*/
@Override
public void onCompleted() {
try {
lastSeenThread = Thread.currentThread();
testObserver.onCompleted();
} finally {
latch.countDown();
}
}
/**
* Get the {@link Notification}s representing each time this {@link Subscriber} was notified of sequence
* completion via {@link #onCompleted}, as a {@link List}.
*
* @return a list of Notifications representing calls to this Subscriber's {@link #onCompleted} method
*/
public List> getOnCompletedEvents() {
return testObserver.getOnCompletedEvents();
}
/**
* Notifies the Subscriber that the {@code Observable} has experienced an error condition.
*
* If the {@code Observable} calls this method, it will not thereafter call {@link #onNext} or
* {@link #onCompleted}.
*
* @param e
* the exception encountered by the Observable
*/
@Override
public void onError(Throwable e) {
try {
lastSeenThread = Thread.currentThread();
testObserver.onError(e);
} finally {
latch.countDown();
}
}
/**
* Get the {@link Throwable}s this {@link Subscriber} was notified of via {@link #onError} as a
* {@link List}.
*
* @return a list of the Throwables that were passed to this Subscriber's {@link #onError} method
*/
public List getOnErrorEvents() {
return testObserver.getOnErrorEvents();
}
/**
* Provides the Subscriber with a new item to observe.
*
* The {@code Observable} may call this method 0 or more times.
*
* The {@code Observable} will not call this method again after it calls either {@link #onCompleted} or
* {@link #onError}.
*
* @param t
* the item emitted by the Observable
*/
@Override
public void onNext(T t) {
lastSeenThread = Thread.currentThread();
testObserver.onNext(t);
}
/**
* Allow calling the protected {@link #request(long)} from unit tests.
*
* @param n the maximum number of items you want the Observable to emit to the Subscriber at this time, or
* {@code Long.MAX_VALUE} if you want the Observable to emit items at its own pace
*/
public void requestMore(long n) {
request(n);
}
/**
* Get the sequence of items observed by this {@link Subscriber}, as an ordered {@link List}.
*
* @return a list of items observed by this Subscriber, in the order in which they were observed
*/
public List getOnNextEvents() {
return testObserver.getOnNextEvents();
}
/**
* Assert that a particular sequence of items was received by this {@link Subscriber} in order.
*
* @param items
* the sequence of items expected to have been observed
* @throws AssertionError
* if the sequence of items observed does not exactly match {@code items}
*/
public void assertReceivedOnNext(List items) {
testObserver.assertReceivedOnNext(items);
}
/**
* Assert that a single terminal event occurred, either {@link #onCompleted} or {@link #onError}.
*
* @throws AssertionError
* if not exactly one terminal event notification was received
*/
public void assertTerminalEvent() {
testObserver.assertTerminalEvent();
}
/**
* Assert that this {@code Subscriber} is unsubscribed.
*
* @throws AssertionError
* if this {@code Subscriber} is not unsubscribed
*/
public void assertUnsubscribed() {
if (!isUnsubscribed()) {
throw new AssertionError("Not unsubscribed.");
}
}
/**
* Assert that this {@code Subscriber} has received no {@code onError} notifications.
*
* @throws AssertionError
* if this {@code Subscriber} has received one or more {@code onError} notifications
*/
public void assertNoErrors() {
if (getOnErrorEvents().size() > 0) {
// can't use AssertionError because (message, cause) doesn't exist until Java 7
throw new RuntimeException("Unexpected onError events: " + getOnErrorEvents().size(), getOnErrorEvents().get(0));
// TODO possibly check for Java7+ and then use AssertionError at runtime (since we always compile with 7)
}
}
/**
* Blocks until this {@link Subscriber} receives a notification that the {@code Observable} is complete
* (either an {@code onCompleted} or {@code onError} notification).
*
* @throws RuntimeException
* if the Subscriber is interrupted before the Observable is able to complete
*/
public void awaitTerminalEvent() {
try {
latch.await();
} catch (InterruptedException e) {
throw new RuntimeException("Interrupted", e);
}
}
/**
* Blocks until this {@link Subscriber} receives a notification that the {@code Observable} is complete
* (either an {@code onCompleted} or {@code onError} notification), or until a timeout expires.
*
* @param timeout
* the duration of the timeout
* @param unit
* the units in which {@code timeout} is expressed
* @throws RuntimeException
* if the Subscriber is interrupted before the Observable is able to complete
*/
public void awaitTerminalEvent(long timeout, TimeUnit unit) {
try {
latch.await(timeout, unit);
} catch (InterruptedException e) {
throw new RuntimeException("Interrupted", e);
}
}
/**
* Blocks until this {@link Subscriber} receives a notification that the {@code Observable} is complete
* (either an {@code onCompleted} or {@code onError} notification), or until a timeout expires; if the
* Subscriber is interrupted before either of these events take place, this method unsubscribes the
* Subscriber from the Observable).
*
* @param timeout
* the duration of the timeout
* @param unit
* the units in which {@code timeout} is expressed
*/
public void awaitTerminalEventAndUnsubscribeOnTimeout(long timeout, TimeUnit unit) {
try {
awaitTerminalEvent(timeout, unit);
} catch (RuntimeException e) {
unsubscribe();
}
}
/**
* Returns the last thread that was in use when an item or notification was received by this
* {@link Subscriber}.
*
* @return the {@code Thread} on which this Subscriber last received an item or notification from the
* Observable it is subscribed to
*/
public Thread getLastSeenThread() {
return lastSeenThread;
}
}