Class TestObserver<T>

java.lang.Object

io.reactivex.rxjava4.observers.BaseTestConsumer<T, TestObserver<T>>

io.reactivex.rxjava4.observers.TestObserver<T>

Type Parameters:

T - the value type

All Implemented Interfaces:

CompletableObserver, MaybeObserver<T>, Observer<T>, SingleObserver<T>, Disposable, AutoCloseable

public class TestObserver<T>
extends BaseTestConsumer<T, TestObserver<T>>
implements Observer<T>, Disposable, MaybeObserver<T>, SingleObserver<T>, CompletableObserver

An Observer, MaybeObserver, SingleObserver and CompletableObserver composite that can record events from Observables, Maybes, Singles and Completables and allows making assertions about them.

You can override the onSubscribe(Disposable), onNext(Object), onError(Throwable), onComplete() and onSuccess(Object) methods but not the others (this is by design).

The TestObserver implements Disposable for convenience where dispose calls cancel.

See Also:

• TestSubscriber

Field Summary

Fields inherited from class BaseTestConsumer

checkSubscriptionOnce, completions, done, errors, lastThread, tag, timeout, values

Modifier and Type	Field	Description
protected boolean	checkSubscriptionOnce
protected long	completions	The number of completions.
protected final CountDownLatch	done	The latch that indicates an onError or onComplete has been called.
protected final List<Throwable>	errors	The list of errors received.
protected Thread	lastThread	The last thread seen by the observer.
protected CharSequence	tag	The optional tag associated with this test consumer.
protected boolean	timeout	Indicates that one of the awaitX method has timed out.
protected final List<T>	values	The list of values received.

Constructor Summary

Constructors

Constructor	Description
TestObserver()	Constructs a non-forwarding TestObserver.
TestObserver(@NonNull Observer<? super T> downstream)	Constructs a forwarding TestObserver.

Method Summary

Modifier and Type	Method	Description
protected final @NonNull TestObserver<T>	assertSubscribed()	Assert that the onSubscribe(Disposable) method was called exactly once.
static <T> @NonNull TestObserver<T>	create()	Constructs a non-forwarding TestObserver.
static <T> @NonNull TestObserver<T>	create(@NonNull Observer<? super T> delegate)	Constructs a forwarding TestObserver.
final void	dispose()	Cancel/dispose this test consumer.
final boolean	hasSubscription()	Returns true if this TestObserver received a subscription.
final boolean	isDisposed()	Returns true if this test consumer was cancelled/disposed.
void	onComplete()	Notifies the Observer that the Observable has finished sending push-based notifications.
void	onError(@NonNull Throwable t)	Notifies the Observer that the Observable has experienced an error condition.
void	onNext(T t)	Provides the Observer with a new item to observe.
void	onSubscribe(@NonNull Disposable d)	Provides the Observer with the means of cancelling (disposing) the connection (channel) with the Observable in both synchronous (from within Observer.onNext(Object)) and asynchronous manner.
void	onSuccess(T value)	Notifies the MaybeObserver with one item and that the Maybe has finished sending push-based notifications.

Methods inherited from class BaseTestConsumer

assertComplete, assertEmpty, assertError, assertError, assertError, assertFailure, assertNoErrors, assertNotComplete, assertNoValues, assertResult, assertValue, assertValue, assertValueAt, assertValueAt, assertValueCount, assertValues, assertValueSequence, assertValuesOnly, await, await, awaitCount, awaitDone, fail, valueAndClass, values, withTag

Modifier and Type	Method	Description
final TestObserver<T>	assertComplete()	Assert that this TestObserver/TestSubscriber received exactly one onComplete event.
final TestObserver<T>	assertEmpty()	Assert that the TestObserver/TestSubscriber has received a Disposable/Subscription via onSubscribe but no other events.
final TestObserver<T>	assertError(@NonNull Predicate<Throwable> errorPredicate)	Asserts that this TestObserver/TestSubscriber received exactly one onError event for which the provided predicate returns true.
final TestObserver<T>	assertError(@NonNull Class<? extends Throwable> errorClass)	Asserts that this TestObserver/TestSubscriber received exactly one onError event which is an instance of the specified errorClass Class.
final TestObserver<T>	assertError(@NonNull Throwable error)	Assert that this TestObserver/TestSubscriber received exactly the specified onError event value.
final TestObserver<T>	assertFailure(@NonNull Class<? extends Throwable> error, T... values)	Assert that the upstream signaled the specified values in order and then failed with a specific class or subclass of Throwable.
final TestObserver<T>	assertNoErrors()	Assert that this TestObserver/TestSubscriber has not received an onError event.
final TestObserver<T>	assertNotComplete()	Assert that this TestObserver/TestSubscriber has not received an onComplete event.
final TestObserver<T>	assertNoValues()	Assert that this TestObserver/TestSubscriber has not received any onNext events.
final TestObserver<T>	assertResult(T... values)	Assert that the upstream signaled the specified values in order and completed normally.
final TestObserver<T>	assertValue(@NonNull Predicate<T> valuePredicate)	Asserts that this TestObserver/TestSubscriber received exactly one onNext value for which the provided predicate returns true.
final TestObserver<T>	assertValue(T value)	Assert that this TestObserver/TestSubscriber received exactly one onNext value which is equal to the given value with respect to Objects.equals(Object, Object).
final TestObserver<T>	assertValueAt(int index, @NonNull Predicate<T> valuePredicate)	Asserts that this TestObserver/TestSubscriber received an onNext value at the given index for the provided predicate returns true.
final TestObserver<T>	assertValueAt(int index, T value)	Asserts that this TestObserver/TestSubscriber received an onNext value at the given index which is equal to the given value with respect to null-safe Objects.equals(Object, Object).
final TestObserver<T>	assertValueCount(int count)	Assert that this TestObserver/TestSubscriber received the specified number onNext events.
final TestObserver<T>	assertValues(T... values)	Assert that the TestObserver/TestSubscriber received only the specified values in the specified order.
final TestObserver<T>	assertValueSequence(@NonNull Iterable<? extends T> sequence)	Assert that the TestObserver/TestSubscriber received only the specified sequence of values in the same order.
final TestObserver<T>	assertValuesOnly(T... values)	Assert that the TestObserver/TestSubscriber received only the specified values in the specified order without terminating.
final TestObserver<T>	await()	Awaits until this TestObserver/TestSubscriber receives an onError or onComplete events.
final boolean	await(long time, @NonNull TimeUnit unit)	Awaits the specified amount of time or until this TestObserver/TestSubscriber receives an onError or onComplete events, whichever happens first.
final TestObserver<T>	awaitCount(int atLeast)	Await until the TestObserver/TestSubscriber receives the given number of items or terminates by sleeping 10 milliseconds at a time up to 5000 milliseconds of timeout.
final TestObserver<T>	awaitDone(long time, @NonNull TimeUnit unit)	Awaits until the internal latch is counted down.
protected final @NonNull AssertionError	fail(@NonNull String message)	Fail with the given message and add the sequence of errors as suppressed ones.
static @NonNull String	valueAndClass(@Nullable Object o)	Appends the class name to a non-null value or returns "null".
final @NonNull List<T>	values()	Returns a shared list of received onNext values or the single onSuccess value.
final TestObserver<T>	withTag(@Nullable CharSequence tag)	Set the tag displayed along with an assertion failure's other state information.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface Disposable

close

Modifier and Type	Method	Description
default void	close()	Dispose the resource, the operation should be idempotent.

Constructor Details

TestObserver

public TestObserver()

Constructs a non-forwarding TestObserver.

TestObserver

public TestObserver(@NonNull
 @NonNull Observer<? super T> downstream)

Constructs a forwarding TestObserver.

Parameters:

downstream - the actual Observer to forward events to

Method Details

create

@NonNull
public static <T> @NonNull TestObserver<T> create()

Constructs a non-forwarding TestObserver.

Type Parameters:

T - the value type received

Returns:

the new TestObserver instance

create

@NonNull
public static <T> @NonNull TestObserver<T> create(@NonNull
 @NonNull Observer<? super T> delegate)

Constructs a forwarding TestObserver.

Type Parameters:

T - the value type received

Parameters:

delegate - the actual Observer to forward events to

Returns:

the new TestObserver instance

onSubscribe

public void onSubscribe(@NonNull
 @NonNull Disposable d)

Description copied from interface: Observer

Provides the Observer with the means of cancelling (disposing) the connection (channel) with the Observable in both synchronous (from within Observer.onNext(Object)) and asynchronous manner.

Specified by:

onSubscribe in interface CompletableObserver

Specified by:

onSubscribe in interface MaybeObserver<T>

Specified by:

onSubscribe in interface Observer<T>

Specified by:

onSubscribe in interface SingleObserver<T>

Parameters:

d - the Disposable instance whose Disposable.dispose() can be called anytime to cancel the connection

onNext

public void onNext(@NonNull
 T t)

Description copied from interface: Observer

Provides the Observer with a new item to observe.

The Observable may call this method 0 or more times.

The Observable will not call this method again after it calls either Observer.onComplete() or Observer.onError(Throwable).

Specified by:

onNext in interface Observer<T>

Parameters:

t - the item emitted by the Observable

onError

public void onError(@NonNull
 @NonNull Throwable t)

Description copied from interface: Observer

Notifies the Observer that the Observable has experienced an error condition.

If the Observable calls this method, it will not thereafter call Observer.onNext(T) or Observer.onComplete().

Specified by:

onError in interface CompletableObserver

Specified by:

onError in interface MaybeObserver<T>

Specified by:

onError in interface Observer<T>

Specified by:

onError in interface SingleObserver<T>

Parameters:

t - the exception encountered by the Observable

onComplete

public void onComplete()

Description copied from interface: Observer

Notifies the Observer that the Observable has finished sending push-based notifications.

The Observable will not call this method if it calls Observer.onError(Throwable).

Specified by:

onComplete in interface CompletableObserver

Specified by:

onComplete in interface MaybeObserver<T>

Specified by:

onComplete in interface Observer<T>

dispose

public final void dispose()

Description copied from class: BaseTestConsumer

Cancel/dispose this test consumer.

Specified by:

dispose in interface Disposable

Specified by:

dispose in class BaseTestConsumer<T, TestObserver<T>>

isDisposed

public final boolean isDisposed()

Description copied from class: BaseTestConsumer

Returns true if this test consumer was cancelled/disposed.

Specified by:

isDisposed in interface Disposable

Specified by:

isDisposed in class BaseTestConsumer<T, TestObserver<T>>

Returns:

true if this test consumer was cancelled/disposed.

hasSubscription

public final boolean hasSubscription()

Returns true if this TestObserver received a subscription.

Returns:

true if this TestObserver received a subscription

assertSubscribed

@NonNull
protected final @NonNull TestObserver<T> assertSubscribed()

Assert that the onSubscribe(Disposable) method was called exactly once.

Specified by:

assertSubscribed in class BaseTestConsumer<T, TestObserver<T>>

Returns:

this

onSuccess

public void onSuccess(@NonNull
 T value)

Description copied from interface: MaybeObserver

Notifies the MaybeObserver with one item and that the Maybe has finished sending push-based notifications.

The Maybe will not call this method if it calls MaybeObserver.onError(Throwable).

Specified by:

onSuccess in interface MaybeObserver<T>

Specified by:

onSuccess in interface SingleObserver<T>

Parameters:

value - the item emitted by the Maybe