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/**
 * 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 java.util.concurrent.*;

import rx.*;
import rx.Observer;
import rx.exceptions.CompositeException;

/**
 * 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;
    /** Holds the initial request value. */
    private final long initialRequest;
    /** The shared no-op observer. */
    private static final Observer INERT = new Observer() {

        @Override
        public void onCompleted() {
            // do nothing
        }

        @Override
        public void onError(Throwable e) {
            // do nothing
        }

        @Override
        public void onNext(Object t) {
            // do nothing
        }

    };

    /**
     * Constructs a TestSubscriber with the initial request to be requested from upstream.
     *
     * @param initialRequest the initial request value, negative value will revert to the default unbounded behavior
     * @since 1.1.0
     */
    @SuppressWarnings("unchecked")
    public TestSubscriber(long initialRequest) {
        this((Observer)INERT, initialRequest);
    }
    
    /**
     * Constructs a TestSubscriber with the initial request to be requested from upstream
     * and a delegate Observer to wrap.
     *
     * @param initialRequest the initial request value, negative value will revert to the default unbounded behavior
     * @param delegate the Observer instance to wrap
     * @throws NullPointerException if delegate is null
     * @since 1.1.0
     */
    public TestSubscriber(Observer delegate, long initialRequest) {
        if (delegate == null) {
            throw new NullPointerException();
        }
        this.testObserver = new TestObserver(delegate);
        this.initialRequest = initialRequest;
    }

    /**
     * Constructs a TestSubscriber which requests Long.MAX_VALUE and delegates events to
     * the given Subscriber.
     * @param delegate the subscriber to delegate to.
     * @throws NullPointerException if delegate is null
     * @since 1.1.0
     */
    public TestSubscriber(Subscriber delegate) {
        this(delegate, -1);
    }

    /**
     * Constructs a TestSubscriber which requests Long.MAX_VALUE and delegates events to
     * the given Observer.
     * @param delegate the observer to delegate to.
     * @throws NullPointerException if delegate is null
     * @since 1.1.0
     */
    public TestSubscriber(Observer delegate) {
        this(delegate, -1);
    }

    /**
     * Constructs a TestSubscriber with an initial request of Long.MAX_VALUE and no delegation.
     */
    public TestSubscriber() {
        this(-1);
    }

    /**
     * Factory method to construct a TestSubscriber with an initial request of Long.MAX_VALUE and no delegation.
     * @return the created TestSubscriber instance
     * @since 1.1.0
     */
    public static  TestSubscriber create() {
        return new TestSubscriber();
    }
    
    /**
     * Factory method to construct a TestSubscriber with the given initial request amount and no delegation.
     * @param initialRequest the initial request amount, negative values revert to the default unbounded mode
     * @return the created TestSubscriber instance
     * @since 1.1.0
     */
    public static  TestSubscriber create(long initialRequest) {
        return new TestSubscriber(initialRequest);
    }
    
    /**
     * Factory method to construct a TestSubscriber which delegates events to the given Observer and
     * issues the given initial request amount.
     * @param delegate the observer to delegate events to
     * @param initialRequest the initial request amount, negative values revert to the default unbounded mode
     * @return the created TestSubscriber instance
     * @throws NullPointerException if delegate is null
     * @since 1.1.0
     */
    public static  TestSubscriber create(Observer delegate, long initialRequest) {
        return new TestSubscriber(delegate, initialRequest);
    }
    
    /**
     * Factory method to construct a TestSubscriber which delegates events to the given Observer and
     * an issues an initial request of Long.MAX_VALUE.
     * @param delegate the observer to delegate events to
     * @return the created TestSubscriber instance
     * @throws NullPointerException if delegate is null
     * @since 1.1.0
     */
    public static  TestSubscriber create(Subscriber delegate) {
        return new TestSubscriber(delegate);
    }
    
    /**
     * Factory method to construct a TestSubscriber which delegates events to the given Subscriber and
     * an issues an initial request of Long.MAX_VALUE.
     * @param delegate the subscriber to delegate events to
     * @return the created TestSubscriber instance
     * @throws NullPointerException if delegate is null
     * @since 1.1.0
     */
    public static  TestSubscriber create(Observer delegate) {
        return new TestSubscriber(delegate);
    }
    
    @Override
    public void onStart() {
        if  (initialRequest >= 0) {
            requestMore(initialRequest);
        }
    }

    /**
     * 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(); } } /** * Returns 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(); } } /** * Returns 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); } /** * Allows 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); } /** * Returns 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(); } /** * Asserts 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); } /** * Asserts 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(); } /** * Asserts 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."); } } /** * Asserts 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() { List onErrorEvents = getOnErrorEvents(); if (onErrorEvents.size() > 0) { AssertionError ae = new AssertionError("Unexpected onError events: " + getOnErrorEvents().size()); if (onErrorEvents.size() == 1) { ae.initCause(getOnErrorEvents().get(0)); } else { ae.initCause(new CompositeException(onErrorEvents)); } throw ae; } } /** * 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). If timeout expires then the Subscriber is unsubscribed 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 { boolean result = latch.await(timeout, unit); if (!result) { // timeout occurred unsubscribe(); } } catch (InterruptedException 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; } /** * Asserts that there is exactly one completion event. * * @throws AssertionError if there were zero, or more than one, onCompleted events * @since 1.1.0 */ public void assertCompleted() { int s = testObserver.getOnCompletedEvents().size(); if (s == 0) { throw new AssertionError("Not completed!"); } else if (s > 1) { throw new AssertionError("Completed multiple times: " + s); } } /** * Asserts that there is no completion event. * * @throws AssertionError if there were one or more than one onCompleted events * @since 1.1.0 */ public void assertNotCompleted() { int s = testObserver.getOnCompletedEvents().size(); if (s == 1) { throw new AssertionError("Completed!"); } else if (s > 1) { throw new AssertionError("Completed multiple times: " + s); } } /** * Asserts that there is exactly one error event which is a subclass of the given class. * * @param clazz the class to check the error against. * @throws AssertionError if there were zero, or more than one, onError events, or if the single onError * event did not carry an error of a subclass of the given class * @since 1.1.0 */ public void assertError(Class clazz) { List err = testObserver.getOnErrorEvents(); if (err.size() == 0) { throw new AssertionError("No errors"); } else if (err.size() > 1) { AssertionError ae = new AssertionError("Multiple errors: " + err.size()); ae.initCause(new CompositeException(err)); throw ae; } else if (!clazz.isInstance(err.get(0))) { AssertionError ae = new AssertionError("Exceptions differ; expected: " + clazz + ", actual: " + err.get(0)); ae.initCause(err.get(0)); throw ae; } } /** * Asserts that there is a single onError event with the exact exception. * * @param throwable the throwable to check * @throws AssertionError if there were zero, or more than one, onError events, or if the single onError * event did not carry an error that matches the specified throwable * @since 1.1.0 */ public void assertError(Throwable throwable) { List err = testObserver.getOnErrorEvents(); if (err.size() == 0) { throw new AssertionError("No errors"); } else if (err.size() > 1) { AssertionError ae = new AssertionError("Multiple errors: " + err.size()); ae.initCause(new CompositeException(err)); throw ae; } else if (!throwable.equals(err.get(0))) { AssertionError ae = new AssertionError("Exceptions differ; expected: " + throwable + ", actual: " + err.get(0)); ae.initCause(err.get(0)); throw ae; } } /** * Asserts that there are no onError and onCompleted events. * * @throws AssertionError if there was either an onError or onCompleted event * @since 1.1.0 */ public void assertNoTerminalEvent() { List err = testObserver.getOnErrorEvents(); int s = testObserver.getOnCompletedEvents().size(); if (err.size() > 0 || s > 0) { if (err.isEmpty()) { throw new AssertionError("Found " + err.size() + " errors and " + s + " completion events instead of none"); } else if (err.size() == 1) { AssertionError ae = new AssertionError("Found " + err.size() + " errors and " + s + " completion events instead of none"); ae.initCause(err.get(0)); throw ae; } else { AssertionError ae = new AssertionError("Found " + err.size() + " errors and " + s + " completion events instead of none"); ae.initCause(new CompositeException(err)); throw ae; } } } /** * Asserts that there are no onNext events received. * * @throws AssertionError if there were any onNext events * @since 1.1.0 */ public void assertNoValues() { int s = testObserver.getOnNextEvents().size(); if (s > 0) { throw new AssertionError("No onNext events expected yet some received: " + s); } } /** * Asserts that the given number of onNext events are received. * * @param count the expected number of onNext events * @throws AssertionError if there were more or fewer onNext events than specified by {@code count} * @since 1.1.0 */ public void assertValueCount(int count) { int s = testObserver.getOnNextEvents().size(); if (s != count) { throw new AssertionError("Number of onNext events differ; expected: " + count + ", actual: " + s); } } /** * Asserts that the received onNext events, in order, are the specified items. * * @param values the items to check * @throws AssertionError if the items emitted do not exactly match those specified by {@code values} * @since 1.1.0 */ public void assertValues(T... values) { assertReceivedOnNext(Arrays.asList(values)); } /** * Asserts that there is only a single received onNext event and that it marks the emission of a specific item. * * @param value the item to check * @throws AssertionError if the Observable does not emit only the single item specified by {@code value} * @since 1.1.0 */ public void assertValue(T value) { assertReceivedOnNext(Collections.singletonList(value)); } }