src/test/java/io/reactivex/rxjava4/observers/TestObserverTest.java - 4.x - githubmirror/RxJava

src/test/java/io/reactivex/rxjava4/observers/TestObserverTest.java
1 220 строк34 KB
David Karnok
4.x: Convert from JUnit 4 to JUnit 6 (#8202)
30 июн 2026, 12:01
30 июн 2026, 12:01531388f
/*
 * Copyright (c) 2016-present, RxJava Contributors.
 *
 * 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 io.reactivex.rxjava4.observers;

import static org.junit.jupiter.api.Assertions.*;
import static org.mockito.Mockito.*;

import java.io.IOException;
import java.util.*;
import java.util.concurrent.Flow.Subscriber;
import java.util.concurrent.TimeUnit;

import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.function.Executable;
import org.mockito.InOrder;

import io.reactivex.rxjava4.core.*;
import io.reactivex.rxjava4.core.Observable;
import io.reactivex.rxjava4.core.Observer;
import io.reactivex.rxjava4.disposables.Disposable;
import io.reactivex.rxjava4.exceptions.TestException;
import io.reactivex.rxjava4.internal.functions.Functions;
import io.reactivex.rxjava4.internal.operators.observable.ObservableScalarXMap.ScalarDisposable;
import io.reactivex.rxjava4.processors.PublishProcessor;
import io.reactivex.rxjava4.schedulers.Schedulers;
import io.reactivex.rxjava4.subscribers.TestSubscriber;
import io.reactivex.rxjava4.testsupport.TestHelper;

public class TestObserverTest extends RxJavaTest {

    static void assertThrowsWithMessage(String message, Class<? extends Throwable> clazz, Executable run) {
        if (message.startsWith("~")) {
            message = message.substring(1);
        }
        assertEquals(message, assertThrows(clazz, run).getMessage());
    }

    static void assertThrowsWithMessageMatchRegex(String regex, Class<? extends Throwable> clazz, Executable run) {
        assertTrue(assertThrows(clazz, run).getMessage().matches(regex));
    }

    private static final String ASSERT_MESSAGE_REGEX  = "\nexpected: (.*)\n\\s*got: (.*)";

    @Test
    public void assertTestObserver() {
        Flowable<Integer> oi = Flowable.fromIterable(Arrays.asList(1, 2));
        TestSubscriber<Integer> subscriber = new TestSubscriber<>();
        oi.subscribe(subscriber);

        subscriber.assertValues(1, 2);
        subscriber.assertValueCount(2);
        subscriber.assertComplete().assertNoErrors();
    }

    @Test
    public void assertNotMatchCount() {
        assertThrows(AssertionError.class, () -> {
            Flowable<Integer> oi = Flowable.fromIterable(Arrays.asList(1, 2));
            TestSubscriber<Integer> subscriber = new TestSubscriber<>();
            oi.subscribe(subscriber);

            subscriber.assertValue(1);
            subscriber.assertValueCount(2);
            subscriber.assertComplete().assertNoErrors();
        });
    }

    @Test
    public void assertNotMatchValue() {
        assertThrows(AssertionError.class, () -> {
            Flowable<Integer> oi = Flowable.fromIterable(Arrays.asList(1, 2));
            TestSubscriber<Integer> subscriber = new TestSubscriber<>();
            oi.subscribe(subscriber);

            subscriber.assertValues(1, 3);
            subscriber.assertValueCount(2);
            subscriber.assertComplete().assertNoErrors();
        });
    }

    @Test
    public void assertTerminalEventNotReceived() {
        assertThrows(AssertionError.class, () -> {
            PublishProcessor<Integer> p = PublishProcessor.create();
            TestSubscriber<Integer> subscriber = new TestSubscriber<>();
            p.subscribe(subscriber);

            p.onNext(1);
            p.onNext(2);

            subscriber.assertValues(1, 2);
            subscriber.assertValueCount(2);
            subscriber.assertComplete().assertNoErrors();
        });
    }

    @Test
    public void wrappingMock() {
        Flowable<Integer> oi = Flowable.fromIterable(Arrays.asList(1, 2));

        Subscriber<Integer> mockSubscriber = TestHelper.mockSubscriber();

        oi.subscribe(new TestSubscriber<>(mockSubscriber));

        InOrder inOrder = inOrder(mockSubscriber);
        inOrder.verify(mockSubscriber, times(1)).onNext(1);
        inOrder.verify(mockSubscriber, times(1)).onNext(2);
        inOrder.verify(mockSubscriber, times(1)).onComplete();
        inOrder.verifyNoMoreInteractions();
    }

    @Test
    public void wrappingMockWhenUnsubscribeInvolved() {
        Flowable<Integer> oi = Flowable.fromIterable(Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9)).take(2);
        Subscriber<Integer> mockSubscriber = TestHelper.mockSubscriber();
        oi.subscribe(new TestSubscriber<>(mockSubscriber));

        InOrder inOrder = inOrder(mockSubscriber);
        inOrder.verify(mockSubscriber, times(1)).onNext(1);
        inOrder.verify(mockSubscriber, times(1)).onNext(2);
        inOrder.verify(mockSubscriber, times(1)).onComplete();
        inOrder.verifyNoMoreInteractions();
    }

    @Test
    public void errorSwallowed() {
        Flowable.error(new RuntimeException()).subscribe(new TestSubscriber<>());
    }

    @Test
    public void nullExpected() {
        TestSubscriber<Integer> ts = new TestSubscriber<>();
        ts.onNext(1);

        try {
            ts.assertValue((Integer) null);
        } catch (AssertionError ex) {
            // this is expected
            return;
        }
        fail("Null element check assertion didn't happen!");
    }

    @Test
    public void nullActual() {
        TestSubscriber<Integer> ts = new TestSubscriber<>();
        ts.onNext(null);

        try {
            ts.assertValue(1);
        } catch (AssertionError ex) {
            // this is expected
            return;
        }
        fail("Null element check assertion didn't happen!");
    }

    @Test
    public void createDelegate() {
        TestObserver<Integer> to1 = TestObserver.create();

        TestObserver<Integer> to = TestObserver.create(to1);

        assertFalse(to.hasSubscription());

        to.onSubscribe(Disposable.empty());

        assertTrue(to.hasSubscription());

        assertFalse(to.isDisposed());

        to.onNext(1);
        to.onError(new TestException());
        to.onComplete();

        to1.assertValue(1).assertError(TestException.class).assertComplete();

        to.dispose();

        assertTrue(to.isDisposed());

        try {
            to.assertNoValues();
            throw new RuntimeException("Should have thrown");
        } catch (AssertionError exc) {
            // expected
        }

        try {
            to.assertValueCount(0);
            throw new RuntimeException("Should have thrown");
        } catch (AssertionError exc) {
            // expected
        }

        to.assertValueSequence(Collections.singletonList(1));

        try {
            to.assertValueSequence(Collections.singletonList(2));
            throw new RuntimeException("Should have thrown");
        } catch (AssertionError exc) {
            // expected
        }
    }

    @Test
    public void assertError() {
        TestObserver<Integer> to = TestObserver.create();

        try {
            to.assertError(TestException.class);
            throw new RuntimeException("Should have thrown");
        } catch (AssertionError ex) {
            // expected
        }

        try {
            to.assertError(new TestException());
            throw new RuntimeException("Should have thrown");
        } catch (AssertionError ex) {
            // expected
        }

        try {
            to.assertError(Functions.<Throwable>alwaysTrue());
            throw new RuntimeException("Should have thrown");
        } catch (AssertionError ex) {
            // expected
        }

        try {
            to.assertSubscribed();
            throw new RuntimeException("Should have thrown");
        } catch (AssertionError exc) {
            // expected
        }

        to.onSubscribe(Disposable.empty());

        to.assertSubscribed();

        to.assertNoErrors();

        TestException ex = new TestException("Forced failure");

        to.onError(ex);

        to.assertError(ex);

        to.assertError(TestException.class);

        to.assertError(Functions.<Throwable>alwaysTrue());

        to.assertError(t -> t.getMessage() != null && t.getMessage().contains("Forced"));

        try {
            to.assertError(new RuntimeException());
            throw new RuntimeException("Should have thrown");
        } catch (AssertionError exc) {
            // expected
        }

        try {
            to.assertError(IOException.class);
            throw new RuntimeException("Should have thrown");
        } catch (AssertionError exc) {
            // expected
        }

        try {
            to.assertError(Functions.<Throwable>alwaysFalse());
            throw new RuntimeException("Should have thrown");
        } catch (AssertionError exc) {
            // expected
        }

        try {
            to.assertNoErrors();
            throw new RuntimeException("Should have thrown");
        } catch (AssertionError exc) {
            // expected
        }

        to.assertValueCount(0);

        to.assertNoValues();
    }

    @Test
    public void emptyObserverEnum() {
        assertEquals(1, TestObserver.EmptyObserver.values().length);
        assertNotNull(TestObserver.EmptyObserver.valueOf("INSTANCE"));
    }

    @Test
    public void valueAndClass() {
        assertEquals("null", TestObserver.valueAndClass(null));
        assertEquals("1 (class: Integer)", TestObserver.valueAndClass(1));
    }

    @Test
    public void assertFailure() {
        TestObserver<Integer> to = TestObserver.create();

        to.onSubscribe(Disposable.empty());

        to.onError(new TestException("Forced failure"));

        to.assertFailure(TestException.class);

        to.onNext(1);

        to.assertFailure(TestException.class, 1);
    }

    @Test
    public void assertFuseable() {
        TestObserver<Integer> to = TestObserver.create();

        to.onSubscribe(Disposable.empty());

        to = TestObserver.create();

        to.onSubscribe(new ScalarDisposable<>(to, 1));
    }

    @Test
    public void assertResult() {
        TestObserver<Integer> to = TestObserver.create();

        to.onSubscribe(Disposable.empty());

        to.onComplete();

        to.assertResult();

        try {
            to.assertResult(1);
            throw new RuntimeException("Should have thrown");
        } catch (AssertionError ex) {
            // expected
        }

        to.onNext(1);

        to.assertResult(1);

        try {
            to.assertResult(2);
            throw new RuntimeException("Should have thrown");
        } catch (AssertionError ex) {
            // expected
        }

        try {
            to.assertResult();
            throw new RuntimeException("Should have thrown");
        } catch (AssertionError ex) {
            // expected
        }

    }

    @Test
    public void await() throws Exception {
        TestObserver<Integer> to = TestObserver.create();

        to.onSubscribe(Disposable.empty());

        assertFalse(to.await(100, TimeUnit.MILLISECONDS));

        to.awaitDone(100, TimeUnit.MILLISECONDS);

        assertTrue(to.isDisposed());

        assertFalse(to.await(100, TimeUnit.MILLISECONDS));

        to.assertNotComplete();
        to.assertNoErrors();

        to.onComplete();

        assertTrue(to.await(100, TimeUnit.MILLISECONDS));

        to.await();

        to.awaitDone(5, TimeUnit.SECONDS);

        to.assertComplete();
        to.assertNoErrors();

        assertTrue(to.await(5, TimeUnit.SECONDS));

        final TestObserver<Integer> to1 = TestObserver.create();

        to1.onSubscribe(Disposable.empty());

        Schedulers.single().scheduleDirect(to1::onComplete, 200, TimeUnit.MILLISECONDS);

        to1.await();
    }

    @Test
    public void onNext() {
        TestObserver<Integer> to = TestObserver.create();

        to.onSubscribe(Disposable.empty());

        assertEquals(0, to.values().size());

        assertEquals(Collections.emptyList(), to.values());

        to.onNext(1);

        assertEquals(Collections.singletonList(1), to.values());

        to.dispose();

        assertTrue(to.isDisposed());

        to.assertValue(1);

        to.onComplete();
    }

    @Test
    public void multipleTerminals() {
        TestObserver<Integer> to = TestObserver.create();

        to.onSubscribe(Disposable.empty());

        to.assertNotComplete();

        to.onComplete();

        try {
            to.assertNotComplete();
            throw new RuntimeException("Should have thrown");
        } catch (Throwable ex) {
            // expected
        }

        to.onComplete();

        try {
            to.assertComplete();
            throw new RuntimeException("Should have thrown");
        } catch (Throwable ex) {
            // expected
        }

        try {
            to.assertNotComplete();
            throw new RuntimeException("Should have thrown");
        } catch (Throwable ex) {
            // expected
        }
    }

    @Test
    public void assertValue() {
        TestObserver<Integer> to = TestObserver.create();

        to.onSubscribe(Disposable.empty());

        try {
            to.assertValue(1);
            throw new RuntimeException("Should have thrown");
        } catch (Throwable ex) {
            // expected
        }

        to.onNext(1);

        to.assertValue(1);

        try {
            to.assertValue(2);
            throw new RuntimeException("Should have thrown");
        } catch (Throwable ex) {
            // expected
        }

        to.onNext(2);

        try {
            to.assertValue(1);
            throw new RuntimeException("Should have thrown");
        } catch (Throwable ex) {
            // expected
        }
    }

    @Test
    public void onNextMisbehave() {
        TestObserver<Integer> to = TestObserver.create();

        to.onNext(1);

        to.assertError(IllegalStateException.class);

        to = TestObserver.create();

        to.onSubscribe(Disposable.empty());

        to.onNext(null);

        to.assertFailure(NullPointerException.class, (Integer)null);
    }

    @Test
    public void awaitTerminalEventInterrupt() {
        final TestObserver<Integer> to = TestObserver.create();

        to.onSubscribe(Disposable.empty());

        Thread.currentThread().interrupt();

        try {
            to.awaitDone(5, TimeUnit.SECONDS);
        } catch (RuntimeException allowed) {
            assertTrue(allowed.getCause() instanceof InterruptedException, allowed.toString());
        }

        // FIXME ? catch consumes this flag
        // assertTrue(Thread.interrupted());

        Thread.currentThread().interrupt();

        try {
            to.awaitDone(5, TimeUnit.SECONDS);
        } catch (RuntimeException allowed) {
            assertTrue(allowed.getCause() instanceof InterruptedException, allowed.toString());
        }

        // FIXME ? catch consumes this flag
        // assertTrue(Thread.interrupted());
    }

    @Test
    public void assertTerminated2() {
        TestObserver<Integer> to = TestObserver.create();

        to.onSubscribe(Disposable.empty());

        to.onError(new TestException());
        to.onError(new IOException());

        try {
            to.assertError(TestException.class);
            throw new RuntimeException("Should have thrown");
        } catch (AssertionError ex) {
            // expected
        }

        to = TestObserver.create();

        to.onSubscribe(Disposable.empty());

        to.onError(new TestException());
        to.onComplete();
    }

    @Test
    public void onSubscribe() {
        TestObserver<Integer> to = TestObserver.create();

        to.onSubscribe(null);

        to.assertError(NullPointerException.class);

        to = TestObserver.create();

        to.onSubscribe(Disposable.empty());

        Disposable d1 = Disposable.empty();

        to.onSubscribe(d1);

        assertTrue(d1.isDisposed());

        to.assertError(IllegalStateException.class);

        to = TestObserver.create();
        to.dispose();

        d1 = Disposable.empty();

        to.onSubscribe(d1);

        assertTrue(d1.isDisposed());

    }

    @Test
    public void assertValueSequence() {
        TestObserver<Integer> to = TestObserver.create();

        to.onSubscribe(Disposable.empty());

        to.onNext(1);
        to.onNext(2);

        try {
            to.assertValueSequence(Collections.<Integer>emptyList());
            throw new RuntimeException("Should have thrown");
        } catch (AssertionError expected) {
            assertTrue(expected.getMessage().startsWith("More values received than expected (0)"), expected.getMessage());
        }

        try {
            to.assertValueSequence(Collections.singletonList(1));
            throw new RuntimeException("Should have thrown");
        } catch (AssertionError expected) {
            assertTrue(expected.getMessage().startsWith("More values received than expected (1)"), expected.getMessage());
        }

        to.assertValueSequence(Arrays.asList(1, 2));

        try {
            to.assertValueSequence(Arrays.asList(1, 2, 3));
            throw new RuntimeException("Should have thrown");
        } catch (AssertionError expected) {
            assertTrue(expected.getMessage().startsWith("Fewer values received than expected (2)"), expected.getMessage());
        }
    }

    @Test
    public void assertEmpty() {
        TestObserver<Integer> to = new TestObserver<>();

        try {
            to.assertEmpty();
            throw new RuntimeException("Should have thrown!");
        } catch (AssertionError ex) {
            // expected
        }

        to.onSubscribe(Disposable.empty());

        to.assertEmpty();

        to.onNext(1);

        try {
            to.assertEmpty();
            throw new RuntimeException("Should have thrown!");
        } catch (AssertionError ex) {
            // expected
        }
    }

    @Test
    public void awaitDoneTimed() {
        TestObserver<Integer> to = new TestObserver<>();

        Thread.currentThread().interrupt();

        try {
            to.awaitDone(5, TimeUnit.SECONDS);
        } catch (RuntimeException ex) {
            assertTrue(ex.getCause() instanceof InterruptedException, ex.toString());
        }
    }

    @Test
    public void assertErrorMultiple() {
        TestObserver<Integer> to = new TestObserver<>();

        TestException e = new TestException();
        to.onError(e);
        to.onError(new TestException());

        try {
            to.assertError(TestException.class);
            throw new RuntimeException("Should have thrown!");
        } catch (AssertionError ex) {
            // expected
        }
        try {
            to.assertError(e);
            throw new RuntimeException("Should have thrown!");
        } catch (AssertionError ex) {
            // expected
        }
        try {
            to.assertError(Functions.<Throwable>alwaysTrue());
            throw new RuntimeException("Should have thrown!");
        } catch (AssertionError ex) {
            // expected
        }
    }

    @Test
    public void errorInPredicate() {
        TestObserver<Object> to = new TestObserver<>();
        to.onError(new RuntimeException());
        try {
            to.assertError(_ -> {
                throw new TestException();
            });
        } catch (TestException ex) {
            // expected
            return;
        }
        fail("Error in predicate but not thrown!");
    }

    @Test
    public void assertComplete() {
        TestObserver<Integer> to = new TestObserver<>();

        to.onSubscribe(Disposable.empty());

        try {
            to.assertComplete();
            throw new RuntimeException("Should have thrown!");
        } catch (AssertionError ex) {
            // expected
        }

        to.onComplete();

        to.assertComplete();

        to.onComplete();

        try {
            to.assertComplete();
            throw new RuntimeException("Should have thrown!");
        } catch (AssertionError ex) {
            // expected
        }
    }

    @Test
    public void completeWithoutOnSubscribe() {
        TestObserver<Integer> to = new TestObserver<>();

        to.onComplete();

        to.assertError(IllegalStateException.class);
    }

    @Test
    public void completeDelegateThrows() {
        var to = new TestObserver<>(new Observer<Integer>() /* NFI */ {

            @Override
            public void onSubscribe(Disposable d) {

            }

            @Override
            public void onNext(Integer value) {

            }

            @Override
            public void onError(Throwable e) {
                throw new TestException();
            }

            @Override
            public void onComplete() {
                throw new TestException();
            }

        });

        to.onSubscribe(Disposable.empty());

        try {
            to.onComplete();
            throw new RuntimeException("Should have thrown!");
        } catch (TestException ex) {
            to.assertComplete().assertNoErrors();
        }
    }

    @Test
    public void errorDelegateThrows() {
        var to = new TestObserver<>(new Observer<Integer>() /* NFI */ {

            @Override
            public void onSubscribe(Disposable d) {

            }

            @Override
            public void onNext(Integer value) {

            }

            @Override
            public void onError(Throwable e) {
                throw new TestException();
            }

            @Override
            public void onComplete() {
                throw new TestException();
            }

        });

        to.onSubscribe(Disposable.empty());

        try {
            to.onError(new IOException());
            throw new RuntimeException("Should have thrown!");
        } catch (TestException ex) {
            to.assertNotComplete().assertError(Throwable.class);
        }
    }

    @Test
    public void completedMeansDisposed() {
        // 2.0.2 - a terminated TestObserver no longer reports isDisposed
        assertFalse(Observable.just(1)
                .test()
                .assertResult(1).isDisposed());
    }

    @Test
    public void errorMeansDisposed() {
        // 2.0.2 - a terminated TestObserver no longer reports isDisposed
        assertFalse(Observable.error(new TestException())
                .test()
                .assertFailure(TestException.class).isDisposed());
    }

    @Test
    public void assertValuePredicateEmpty() {
        assertThrowsWithMessage("No values (latch = 0, values = 0, errors = 0, completions = 1)", AssertionError.class, () -> {
            TestObserver<Object> to = new TestObserver<>();

            Observable.empty().subscribe(to);

            to.assertValue(_ -> false);
        });
    }

    @Test
    public void assertValuePredicateMatch() {
        TestObserver<Integer> to = new TestObserver<>();

        Observable.just(1).subscribe(to);

        to.assertValue(o -> o == 1);
    }

    @Test
    public void assertValuePredicateNoMatch() {
        assertThrowsWithMessage("Value 1 (class: Integer) at position 0 did not pass the predicate "
                + "(latch = 0, values = 1, errors = 0, completions = 1)", AssertionError.class, () -> {
            TestObserver<Integer> to = new TestObserver<>();

            Observable.just(1).subscribe(to);

            to.assertValue(o -> o != 1);
        });
    }

    @Test
    public void assertValuePredicateMatchButMore() {
        assertThrowsWithMessage("The first value passed the predicate but this consumer received more than one value "
                + "(latch = 0, values = 2, errors = 0, completions = 1)", AssertionError.class, () -> {
            TestObserver<Integer> to = new TestObserver<>();

            Observable.just(1, 2).subscribe(to);

            to.assertValue(o -> o == 1);
        });
    }

    @Test
    public void assertValueAtPredicateEmpty() {
        assertThrowsWithMessage("No values (latch = 0, values = 0, errors = 0, completions = 1)", AssertionError.class, () -> {
            TestObserver<Object> to = new TestObserver<>();

            Observable.empty().subscribe(to);

            to.assertValueAt(0, _ -> false);
        });
    }

    @Test
    public void assertValueAtPredicateMatch() {
        TestObserver<Integer> to = new TestObserver<>();

        Observable.just(1, 2).subscribe(to);

        to.assertValueAt(1, o -> o == 2);
    }

    @Test
    public void assertValueAtPredicateNoMatch() {
        assertThrowsWithMessage("Value 3 (class: Integer) at position 2 did not pass the predicate "
                + "(latch = 0, values = 3, errors = 0, completions = 1)", AssertionError.class, () -> {
            TestObserver<Integer> to = new TestObserver<>();

            Observable.just(1, 2, 3).subscribe(to);

            to.assertValueAt(2, o -> o != 3);
        });
    }

    @Test
    public void assertValueAtInvalidIndex() {
        assertThrowsWithMessage("Index 2 is out of range [0, 2) (latch = 0, values = 2, errors = 0, completions = 1)", AssertionError.class, () -> {
            TestObserver<Integer> to = new TestObserver<>();

            Observable.just(1, 2).subscribe(to);

            to.assertValueAt(2, o -> o == 1);
        });
    }

    @Test
    public void assertValueAtInvalidIndexNegative() {
        assertThrowsWithMessage("Index -2 is out of range [0, 2) (latch = 0, values = 2, errors = 0, completions = 1)", AssertionError.class, () -> {
            TestObserver<Integer> to = new TestObserver<>();

            Observable.just(1, 2).subscribe(to);

            to.assertValueAt(-2, o -> o == 1);
        });
    }

    @Test
    public void assertValueAtIndexEmpty() {
        assertThrowsWithMessage("No values (latch = 0, values = 0, errors = 0, completions = 1)", AssertionError.class, () -> {
            TestObserver<Object> to = new TestObserver<>();

            Observable.empty().subscribe(to);

            to.assertValueAt(0, "a");
        });
    }

    @Test
    public void assertValueAtIndexMatch() {
        TestObserver<String> to = new TestObserver<>();

        Observable.just("a", "b").subscribe(to);

        to.assertValueAt(1, "b");
    }

    @Test
    public void assertValueAtIndexNoMatch() {
        assertThrowsWithMessage("""
                ~
                expected: b (class: String)
                got: c (class: String); Value at position 2 differ \
                (latch = 0, values = 3, errors = 0, completions = 1)""",
                AssertionError.class, () -> {
            TestObserver<String> to = new TestObserver<>();

            Observable.just("a", "b", "c").subscribe(to);

            to.assertValueAt(2, "b");
        });
    }

    @Test
    public void assertValueAtIndexThrowsMessageMatchRegex() {
        assertThrowsWithMessageMatchRegex(ASSERT_MESSAGE_REGEX, AssertionError.class, () -> {
            TestObserver<String> to = new TestObserver<>();

            Observable.just("a", "b", "c").subscribe(to);

            to.assertValueAt(2, "b");
        });
    }

    @Test
    public void assertValuesCountNoMatch() {
        assertThrowsWithMessage("""
                ~
                expected: 2 [a, b]
                got: 3 [a, b, c]; \
                Value count differs (latch = 0, values = 3, errors = 0, completions = 1)""", AssertionError.class, () -> {
            TestObserver<String> to = new TestObserver<>();

            Observable.just("a", "b", "c").subscribe(to);

            to.assertValues("a", "b");
        });
    }

    @Test
    public void assertValuesCountThrowsMessageMatchRegex() {
        assertThrowsWithMessageMatchRegex(ASSERT_MESSAGE_REGEX, AssertionError.class, () -> {
            TestObserver<String> to = new TestObserver<>();

            Observable.just("a", "b", "c").subscribe(to);

            to.assertValues("a", "b");
        });
    }

    @Test
    public void assertValuesNoMatch() {
        assertThrowsWithMessage("""
                ~
                expected: d (class: String)
                got: c (class: String); Value at position 2 differ \
                (latch = 0, values = 3, errors = 0, completions = 1)""", AssertionError.class, () -> {
            TestObserver<String> to = new TestObserver<>();

            Observable.just("a", "b", "c").subscribe(to);

            to.assertValues("a", "b", "d");
        });
    }

    @Test
    public void assertValuesThrowsMessageMatchRegex() {
        assertThrowsWithMessageMatchRegex(ASSERT_MESSAGE_REGEX, AssertionError.class, () -> {
            TestObserver<String> to = new TestObserver<>();

            Observable.just("a", "b", "c").subscribe(to);

            to.assertValues("a", "b", "d");
        });
    }

    @Test
    public void assertValueCountNoMatch() {
        assertThrowsWithMessage("\nexpected: 2\ngot: 3; Value counts differ (latch = 0, values = 3, errors = 0, completions = 1)", AssertionError.class, () -> {
            TestObserver<String> to = new TestObserver<>();

            Observable.just("a", "b", "c").subscribe(to);

            to.assertValueCount(2);
        });
    }

    @Test
    public void assertValueCountThrowsMessageMatchRegex() {
        assertThrowsWithMessageMatchRegex(ASSERT_MESSAGE_REGEX, AssertionError.class, () -> {
            TestObserver<String> to = new TestObserver<>();

            Observable.just("a", "b", "c").subscribe(to);

            to.assertValueCount(2);
        });
    }

    @Test
    public void assertValueSequenceNoMatch() {
        assertThrowsWithMessage("""
                ~
                expected: d (class: String)
                got: c (class: String); Value at position 2 differ \
                (latch = 0, values = 3, errors = 0, completions = 1)""", AssertionError.class, () -> {
            TestObserver<String> to = new TestObserver<>();

            Observable.just("a", "b", "c").subscribe(to);

            to.assertValueSequence(Arrays.asList("a", "b", "d"));
        });
    }

    @Test
    public void assertValueSequenceThrowsMessageMatchRegex() {
        assertThrowsWithMessageMatchRegex(ASSERT_MESSAGE_REGEX, AssertionError.class, () -> {
            TestObserver<String> to = new TestObserver<>();

            Observable.just("a", "b", "c").subscribe(to);

            to.assertValueSequence(Arrays.asList("a", "b", "d"));
        });
    }

    @Test
    public void assertValueAtIndexInvalidIndex() {
        assertThrowsWithMessage("Index 2 is out of range [0, 2) (latch = 0, values = 2, errors = 0, completions = 1)", AssertionError.class, () -> {
            TestObserver<String> to = new TestObserver<>();

            Observable.just("a", "b").subscribe(to);

            to.assertValueAt(2, "c");
        });
    }

    @Test
    public void assertValueAtIndexInvalidIndexNegative() {
        assertThrowsWithMessage("Index -2 is out of range [0, 2) (latch = 0, values = 2, errors = 0, completions = 1)", AssertionError.class, () -> {
            TestObserver<String> to = new TestObserver<>();

            Observable.just("a", "b").subscribe(to);

            to.assertValueAt(-2, "c");
        });
    }

    @Test
    public void withTag() {
        try {
            for (int i = 1; i < 3; i++) {
                Observable.just(i)
                .test()
                .withTag("testing with item=" + i)
                .assertResult(1)
                ;
            }
            throw new RuntimeException("Should have thrown!");
        } catch (AssertionError ex) {
            assertTrue(ex.toString().contains("testing with item=2"), ex.toString());
        }
    }

    @Test
    public void assertValuesOnly() {
        TestObserver<Integer> to = TestObserver.create();
        to.onSubscribe(Disposable.empty());
        to.assertValuesOnly();

        to.onNext(5);
        to.assertValuesOnly(5);

        to.onNext(-1);
        to.assertValuesOnly(5, -1);
    }

    @Test
    public void assertValuesOnlyThrowsOnUnexpectedValue() {
        TestObserver<Integer> to = TestObserver.create();
        to.onSubscribe(Disposable.empty());
        to.assertValuesOnly();

        to.onNext(5);
        to.assertValuesOnly(5);

        to.onNext(-1);

        try {
            to.assertValuesOnly(5);
            throw new RuntimeException();
        } catch (AssertionError ex) {
            // expected
        }
    }

    @Test
    public void assertValuesOnlyThrowsWhenCompleted() {
        TestObserver<Integer> to = TestObserver.create();
        to.onSubscribe(Disposable.empty());

        to.onComplete();

        try {
            to.assertValuesOnly();
            throw new RuntimeException();
        } catch (AssertionError ex) {
            // expected
        }
    }

    @Test
    public void assertValuesOnlyThrowsWhenErrored() {
        TestObserver<Integer> to = TestObserver.create();
        to.onSubscribe(Disposable.empty());

        to.onError(new TestException());

        try {
            to.assertValuesOnly();
            throw new RuntimeException();
        } catch (AssertionError ex) {
            // expected
        }
    }

    @Test
    public void onErrorIsNull() {
        TestObserver<Integer> to = TestObserver.create();
        to.onSubscribe(Disposable.empty());

        to.onError(null);

        to.assertFailure(NullPointerException.class);
    }

    @Test
    public void awaitCountTimeout() {
        TestObserver<Integer> to = TestObserver.create();
        to.onSubscribe(Disposable.empty());
        to.awaitCount(1);
        assertTrue(to.timeout);
    }

    @Test
    public void awaitCountInterrupted() {
        assertThrows(RuntimeException.class, () -> {
            try {
                TestObserver<Integer> to = TestObserver.create();
                to.onSubscribe(Disposable.empty());
                Thread.currentThread().interrupt();
                to.awaitCount(1);
            } finally {
                Thread.interrupted();
            }
        });
    }
}