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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.annotations.Experimental;
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}.
 * @param  the value type
 */
public class TestSubscriber extends Subscriber {

    private final Observer delegate;

    private final List values;

    private final List errors;

    /** The number of onCompleted() calls. */
    private int completions;

    private final CountDownLatch latch = new CountDownLatch(1);

    /** Written after an onNext value has been added to the {@link #values} list. */
    private volatile int valueCount;

    private volatile Thread lastSeenThread;
    /** 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.delegate = delegate;
        if (initialRequest >= 0L) {
            this.request(initialRequest);
        }

        this.values = new ArrayList();
        this.errors = new ArrayList();
    }

    /**
     * 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.
     * @param  the value type
     * @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  the value type
     * @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  the value type
     * @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 Subscriber and
     * an issues an initial request of Long.MAX_VALUE.
     * @param  the value type
     * @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(Subscriber delegate) {
        return new TestSubscriber(delegate);
    }

    /**
     * Factory method to construct a TestSubscriber which delegates events to the given Observer and
     * an issues an initial request of Long.MAX_VALUE.
     * @param  the value type
     * @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(Observer delegate) {
        return new TestSubscriber(delegate);
    }

    /**
     * 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 { completions++; lastSeenThread = Thread.currentThread(); delegate.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 * * @deprecated use {@link #getCompletions()} instead. */ @Deprecated public List> getOnCompletedEvents() { int c = completions; List> result = new ArrayList>(c != 0 ? c : 1); for (int i = 0; i < c; i++) { result.add(Notification.createOnCompleted()); } return result; } /** * Returns the number of times onCompleted was called on this TestSubscriber. * @return the number of times onCompleted was called on this TestSubscriber. * @since (if this graduates from Experimental/Beta to supported, replace this parenthetical with the release number) */ @Experimental public final int getCompletions() { return completions; } /** * 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(); errors.add(e); delegate.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 errors; } /** * 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(); values.add(t); valueCount = values.size(); delegate.onNext(t); } /** * Returns the committed number of onNext elements that are safe to be * read from {@link #getOnNextEvents()} other threads. * @return the committed number of onNext elements */ public final int getValueCount() { return valueCount; } /** * 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 values; } /** * 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) { if (values.size() != items.size()) { assertionError("Number of items does not match. Provided: " + items.size() + " Actual: " + values.size() + ".\n" + "Provided values: " + items + "\n" + "Actual values: " + values + "\n"); } for (int i = 0; i < items.size(); i++) { assertItem(items.get(i), i); } } private void assertItem(T expected, int i) { T actual = values.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"); } } /** * Wait until the current committed value count is less than the expected amount * by sleeping 1 unit at most timeout times and return true if at least * the required amount of onNext values have been received. * @param expected the expected number of onNext events * @param timeout the time to wait for the events * @param unit the time unit of waiting * @return true if the expected number of onNext events happened * @throws RuntimeException if the sleep is interrupted * @since (if this graduates from Experimental/Beta to supported, replace this parenthetical with the release number) */ @Experimental public final boolean awaitValueCount(int expected, long timeout, TimeUnit unit) { while (timeout != 0 && valueCount < expected) { try { unit.sleep(1); } catch (InterruptedException e) { throw new IllegalStateException("Interrupted", e); } timeout--; } return valueCount >= expected; } /** * 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() { if (errors.size() > 1) { assertionError("Too many onError events: " + errors.size()); } if (completions > 1) { assertionError("Too many onCompleted events: " + completions); } if (completions == 1 && errors.size() == 1) { assertionError("Received both an onError and onCompleted. Should be one or the other."); } if (completions == 0 && errors.isEmpty()) { assertionError("No terminal events received."); } } /** * Asserts that this {@code Subscriber} is unsubscribed. * * @throws AssertionError * if this {@code Subscriber} is not unsubscribed */ public void assertUnsubscribed() { if (!isUnsubscribed()) { 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.isEmpty()) { assertionError("Unexpected onError events"); } } /** * 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 IllegalStateException("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 IllegalStateException("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 = completions; if (s == 0) { assertionError("Not completed!"); } else if (s > 1) { 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 = completions; if (s == 1) { assertionError("Completed!"); } else if (s > 1) { 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 = errors; if (err.isEmpty()) { 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 = errors; if (err.isEmpty()) { assertionError("No errors"); } else if (err.size() > 1) { assertionError("Multiple errors"); } else if (!throwable.equals(err.get(0))) { assertionError("Exceptions differ; expected: " + throwable + ", actual: " + err.get(0)); } } /** * 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 = errors; int s = completions; if (!err.isEmpty() || s > 0) { if (err.isEmpty()) { assertionError("Found " + err.size() + " errors and " + s + " completion events instead of none"); } else if (err.size() == 1) { assertionError("Found " + err.size() + " errors and " + s + " completion events instead of none"); } else { assertionError("Found " + err.size() + " errors and " + s + " completion events instead of none"); } } } /** * 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 = values.size(); if (s != 0) { 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 = values.size(); if (s != count) { 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)); } /** * 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 = completions; b.append(c) .append(" completion"); if (c != 1) { b.append('s'); } b.append(')'); if (!errors.isEmpty()) { int size = errors.size(); b.append(" (+") .append(size) .append(" error"); if (size != 1) { b.append('s'); } b.append(')'); } AssertionError ae = new AssertionError(b.toString()); if (!errors.isEmpty()) { if (errors.size() == 1) { ae.initCause(errors.get(0)); } else { ae.initCause(new CompositeException(errors)); } } throw ae; } /** * Assert that the TestSubscriber contains the given first and optional rest values exactly * and if so, clears the internal list of values. *

*

     * TestSubscriber ts = new TestSubscriber();
     *
     * ts.onNext(1);
     *
     * ts.assertValuesAndClear(1);
     *
     * ts.onNext(2);
     * ts.onNext(3);
     *
     * ts.assertValuesAndClear(2, 3); // no mention of 1
     * 
* @param expectedFirstValue the expected first value * @param expectedRestValues the optional rest values * @since (if this graduates from Experimental/Beta to supported, replace this parenthetical with the release number) */ @Experimental public final void assertValuesAndClear(T expectedFirstValue, T... expectedRestValues) { int n = 1 + expectedRestValues.length; assertValueCount(n); assertItem(expectedFirstValue, 0); for (int i = 0; i < expectedRestValues.length; i++) { assertItem(expectedRestValues[i], i + 1); } values.clear(); } }