/*
* Copyright 2015 MongoDB, 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 com.mongodb.async.client;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.CountDownLatch;
public class TestObserver<T> implements Observer<T> {
private final Observer<T> delegate;
private final CountDownLatch latch = new CountDownLatch(1);
private final ArrayList<T> onNextEvents = new ArrayList<T>();
private final ArrayList<Throwable> onErrorEvents = new ArrayList<Throwable>();
private final ArrayList<Void> onCompleteEvents = new ArrayList<Void>();
private Subscription subscription;
public TestObserver(final Observer<T> delegate) {
this.delegate = delegate;
}
public TestObserver() {
this(new Observer<T>() {
@Override
public void onSubscribe(final Subscription subscription) {
// do nothing
}
@Override
public void onNext(final T result) {
// do nothing
}
@Override
public void onComplete() {
// do nothing
}
@Override
public void onError(final Throwable e) {
// do nothing
}
});
}
@Override
public void onSubscribe(final Subscription subscription) {
this.subscription = subscription;
delegate.onSubscribe(subscription);
}
/**
* Provides the Subscriber with a new item to observe.
* <p>
* The {@link Observable} may call this method 0 or more times.
* </p>
* <p>
* The {@link Observable} will not call this method again after it calls either {@link #onComplete} or
* {@link #onError}.
* </p>
* @param result the item emitted by the obserable
*/
@Override
public void onNext(final T result) {
onNextEvents.add(result);
delegate.onNext(result);
}
/**
* Notifies the Subscriber that the obserable has experienced an error condition.
* <p>
* If the obserable calls this method, it will not thereafter call {@link #onNext} or
* {@link #onComplete}.
* </p>
*
* @param e the exception encountered by the obserable
*/
@Override
public void onError(final Throwable e) {
try {
onErrorEvents.add(e);
delegate.onError(e);
} finally {
latch.countDown();
}
}
/**
* Notifies the Subscriber that the obserable has finished sending push-based notifications.
* <p>
* The obserable will not call this method if it calls {@link #onError}.
* </p>
*/
@Override
public void onComplete() {
try {
onCompleteEvents.add(null);
delegate.onComplete();
} finally {
latch.countDown();
}
}
/**
* Allow calling the protected {@link Subscription#request(long)} from unit tests.
*
* @param n the maximum number of items you want the obserable to emit to the Subscriber at this time, or
* {@code Long.MAX_VALUE} if you want the obserable to emit items at its own pace
*/
public void requestMore(final long n) {
subscription.request(n);
}
/**
* Get the {@link Throwable}s this {@link Observer} 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<Throwable> getOnErrorEvents() {
return onErrorEvents;
}
/**
* Get the sequence of items observed by this {@link Observer}, as an ordered {@link List}.
*
* @return a list of items observed by this Subscriber, in the order in which they were observed
*/
public List<T> getOnNextEvents() {
return onNextEvents;
}
/**
* Returns the subscription to the this {@link Observer}.
*
* @return the subscription or null if not subscribed to
*/
public Subscription getSubscription() {
return subscription;
}
/**
* Assert that a particular sequence of items was received by this {@link Observer} 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(final List<T> items) {
if (getOnNextEvents().size() != items.size()) {
throw new AssertionError("Number of items does not match. Provided: " + items.size() + " Actual: " + getOnNextEvents().size());
}
for (int i = 0; i < items.size(); i++) {
if (items.get(i) == null) {
// check for null equality
if (onNextEvents.get(i) != null) {
throw new AssertionError("Value at index: " + i + " expected to be [null] but was: [" + getOnNextEvents().get(i) + "]");
}
} else if (!items.get(i).equals(getOnNextEvents().get(i))) {
throw new AssertionError("Value at index: " + i + " expected to be ["
+ items.get(i) + "] (" + items.get(i).getClass().getSimpleName() + ") but was: [" + getOnNextEvents().get(i)
+ "] (" + getOnNextEvents().get(i).getClass().getSimpleName() + ")");
}
}
}
/**
* Assert that a single terminal event occurred, either {@link #onComplete} or {@link #onError}.
*
* @throws AssertionError if not exactly one terminal event notification was received
*/
public void assertTerminalEvent() {
if (onErrorEvents.size() > 1) {
throw new AssertionError("Too many onError events: " + onErrorEvents.size());
}
if (onCompleteEvents.size() > 1) {
throw new AssertionError("Too many onCompleted events: " + onCompleteEvents.size());
}
if (onCompleteEvents.size() == 1 && onErrorEvents.size() == 1) {
throw new AssertionError("Received both an onError and onCompleted. Should be one or the other.");
}
if (onCompleteEvents.size() == 0 && onErrorEvents.size() == 0) {
throw new AssertionError("No terminal events received.");
}
}
/**
* Assert that no terminal event occurred, either {@link #onComplete} or {@link #onError}.
*
* @throws AssertionError if a terminal event notification was received
*/
public void assertNoTerminalEvent() {
if (onCompleteEvents.size() > 0 || onErrorEvents.size() > 0) {
throw new AssertionError("Terminal events received.");
}
}
/**
* Assert that the {@link Subscription} is unsubscribed.
*
* @throws AssertionError if this {@link Subscription} is not unsubscribed
*/
public void assertUnsubscribed() {
if (subscription == null || !subscription.isUnsubscribed()) {
throw new AssertionError("Not unsubscribed.");
}
}
/**
* Assert that the {@link Subscription} is subscribed.
*
* @throws AssertionError if this {@link Subscription} is not subscribed
*/
public void assertSubscribed() {
if (subscription == null || subscription.isUnsubscribed()) {
throw new AssertionError("Not subscribed.");
}
}
/**
* Assert that this {@link Observer} has received no {@code onError} notifications.
*
* @throws AssertionError if this {@link Observer} has received one or more {@link #onError} notifications
*/
public void assertNoErrors() {
if (onErrorEvents.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));
}
}
/**
* Assert that this {@link Observer} has received an {@code onError} notification.
*
* @throws AssertionError if this {@link Observer} did not received an {@link #onError} notifications
*/
public void assertErrored() {
if (onErrorEvents.size() == 0) {
// can't use AssertionError because (message, cause) doesn't exist until Java 7
throw new RuntimeException("No onError events");
}
}
}