src/main/java/rx/observers/TestObserver.java
/**
* 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.*;
import rx.Notification;
import rx.Observer;
import rx.exceptions.CompositeException;
/**
* Observer usable for unit testing to perform assertions, inspect received events or wrap a mocked Observer.
* @param <T> the observed value type
* @deprecated use the {@link TestSubscriber} instead.
*/
@Deprecated
public class TestObserver<T> implements Observer<T> {
private final Observer<T> delegate;
private final List<T> onNextEvents = new ArrayList<T>();
private final List<Throwable> onErrorEvents = new ArrayList<Throwable>();
private final List<Notification<T>> onCompletedEvents = new ArrayList<Notification<T>>();
public TestObserver(Observer<T> delegate) {
this.delegate = delegate;
}
@SuppressWarnings("unchecked")
public TestObserver() {
this.delegate = (Observer<T>) INERT;
}
@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()) {
assertionError("Number of items does not match. Provided: " + items.size() + " Actual: " + onNextEvents.size()
+ ".\n"
+ "Provided values: " + items
+ "\n"
+ "Actual values: " + onNextEvents
+ "\n");
}
for (int i = 0; i < items.size(); i++) {
T expected = items.get(i);
T actual = onNextEvents.get(i);
if (expected == null) {
// check for null equality
if (actual != null) {
assertionError("Value at index: " + i + " expected to be [null] but was: [" + actual + "]\n");
}
} else if (!expected.equals(actual)) {
assertionError("Value at index: " + i
+ " expected to be [" + expected + "] (" + expected.getClass().getSimpleName()
+ ") but was: [" + actual + "] (" + (actual != null ? actual.getClass().getSimpleName() : "null") + ")\n");
}
}
}
/**
* 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) {
assertionError("Too many onError events: " + onErrorEvents.size());
}
if (onCompletedEvents.size() > 1) {
assertionError("Too many onCompleted events: " + onCompletedEvents.size());
}
if (onCompletedEvents.size() == 1 && onErrorEvents.size() == 1) {
assertionError("Received both an onError and onCompleted. Should be one or the other.");
}
if (onCompletedEvents.isEmpty() && onErrorEvents.isEmpty()) {
assertionError("No terminal events received.");
}
}
/**
* Combines an assertion error message with the current completion and error state of this
* TestSubscriber, giving more information when some assertXXX check fails.
* @param message the message to use for the error
*/
final void assertionError(String message) {
StringBuilder b = new StringBuilder(message.length() + 32);
b.append(message)
.append(" (");
int c = onCompletedEvents.size();
b.append(c)
.append(" completion");
if (c != 1) {
b.append('s');
}
b.append(')');
if (!onErrorEvents.isEmpty()) {
int size = onErrorEvents.size();
b.append(" (+")
.append(size)
.append(" error");
if (size != 1) {
b.append('s');
}
b.append(')');
}
AssertionError ae = new AssertionError(b.toString());
if (!onErrorEvents.isEmpty()) {
if (onErrorEvents.size() == 1) {
ae.initCause(onErrorEvents.get(0));
} else {
ae.initCause(new CompositeException(onErrorEvents));
}
}
throw ae;
}
// do nothing ... including swallowing errors
private static final Observer<Object> INERT = new Observer<Object>() {
@Override
public void onCompleted() {
// deliberately ignored
}
@Override
public void onError(Throwable e) {
// deliberately ignored
}
@Override
public void onNext(Object t) {
// deliberately ignored
}
};
}