/**
* 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.ArrayList;
import java.util.Collections;
import java.util.List;
import rx.Notification;
import rx.Observer;
/**
* Observer usable for unit testing to perform assertions, inspect received events or wrap a mocked Observer.
*/
public class TestObserver<T> implements Observer<T> {
private final Observer<T> delegate;
private final ArrayList<T> onNextEvents = new ArrayList<T>();
private final ArrayList<Throwable> onErrorEvents = new ArrayList<Throwable>();
private final ArrayList<Notification<T>> onCompletedEvents = new ArrayList<Notification<T>>();
public TestObserver(Observer<T> delegate) {
this.delegate = delegate;
}
public TestObserver() {
this.delegate = Observers.empty();
}
@Override
public void onCompleted() {
onCompletedEvents.add(Notification.<T> createOnCompleted());
delegate.onCompleted();
}
/**
* Get the {@link Notification}s representing each time this observer was notified of sequence completion
* via {@link #onCompleted}, as a {@link List}.
*
* @return a list of Notifications representing calls to this observer's {@link #onCompleted} method
*/
public List<Notification<T>> getOnCompletedEvents() {
return Collections.unmodifiableList(onCompletedEvents);
}
@Override
public void onError(Throwable e) {
onErrorEvents.add(e);
delegate.onError(e);
}
/**
* Get the {@link Throwable}s this observer was notified of via {@link #onError} as a {@link List}.
*
* @return a list of Throwables passed to this observer's {@link #onError} method
*/
public List<Throwable> getOnErrorEvents() {
return Collections.unmodifiableList(onErrorEvents);
}
@Override
public void onNext(T t) {
onNextEvents.add(t);
delegate.onNext(t);
}
/**
* Get the sequence of items observed by this observer, as an ordered {@link List}.
*
* @return a list of items observed by this observer, in the order in which they were observed
*/
public List<T> getOnNextEvents() {
return Collections.unmodifiableList(onNextEvents);
}
/**
* Get a list containing all of the items and notifications received by this observer, where the items
* will be given as-is, any error notifications will be represented by their {@code Throwable}s, and any
* sequence-complete notifications will be represented by their {@code Notification} objects.
*
* @return a {@link List} containing one item for each item or notification received by this observer, in
* the order in which they were observed or received
*/
public List<Object> getEvents() {
ArrayList<Object> events = new ArrayList<Object>();
events.add(onNextEvents);
events.add(onErrorEvents);
events.add(onCompletedEvents);
return Collections.unmodifiableList(events);
}
/**
* Assert that a particular sequence of items was received 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<T> items) {
if (onNextEvents.size() != items.size()) {
throw new AssertionError("Number of items does not match. Provided: " + items.size() + " Actual: " + onNextEvents.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: [" + onNextEvents.get(i) + "]");
}
} else if (!items.get(i).equals(onNextEvents.get(i))) {
throw new AssertionError("Value at index: " + i + " expected to be [" + items.get(i) + "] (" + items.get(i).getClass().getSimpleName() + ") but was: [" + onNextEvents.get(i) + "] (" + onNextEvents.get(i).getClass().getSimpleName() + ")");
}
}
}
/**
* 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() {
if (onErrorEvents.size() > 1) {
throw new AssertionError("Too many onError events: " + onErrorEvents.size());
}
if (onCompletedEvents.size() > 1) {
throw new AssertionError("Too many onCompleted events: " + onCompletedEvents.size());
}
if (onCompletedEvents.size() == 1 && onErrorEvents.size() == 1) {
throw new AssertionError("Received both an onError and onCompleted. Should be one or the other.");
}
if (onCompletedEvents.size() == 0 && onErrorEvents.size() == 0) {
throw new AssertionError("No terminal events received.");
}
}
}