JAVA-11499 move rxjava* modules to new rxjava-modules (#12342)

* JAVA-11499 move rxjava* modules to new rxjava-modules

* JAVA-11499 addressed PR comments
This commit is contained in:
Keerthi
2022-06-19 01:51:25 +10:00
committed by GitHub
parent 467d2d5b3a
commit eb99a50559
64 changed files with 79 additions and 111 deletions

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## RxJava Operators
This module contains articles about RxJava Operators
### Related Articles:
- [Mathematical and Aggregate Operators in RxJava](https://www.baeldung.com/rxjava-math)
- [Observable Utility Operators in RxJava](https://www.baeldung.com/rxjava-observable-operators)
- [Implementing Custom Operators in RxJava](https://www.baeldung.com/rxjava-custom-operators)
- [Converting Synchronous and Asynchronous APIs to Observables using RxJava2](https://www.baeldung.com/rxjava-apis-to-observables)

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<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<artifactId>rxjava-operators</artifactId>
<version>1.0-SNAPSHOT</version>
<name>rxjava-operators</name>
<parent>
<groupId>com.baeldung.rxjava-modules</groupId>
<artifactId>rxjava-modules</artifactId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<dependencies>
<!-- https://mvnrepository.com/artifact/com.github.akarnokd/rxjava2-extensions -->
<dependency>
<groupId>com.github.akarnokd</groupId>
<artifactId>rxjava2-extensions</artifactId>
<version>${rxjava2.ext.version}</version>
</dependency>
</dependencies>
<properties>
<rxjava2.ext.version>0.20.4</rxjava2.ext.version>
</properties>
</project>

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package com.baeldung.rxjava.operator;
import rx.Observable.Operator;
import rx.Subscriber;
public class ToCleanString implements Operator<String, String> {
public static ToCleanString toCleanString() {
return new ToCleanString();
}
private ToCleanString() {
super();
}
@Override
public Subscriber<? super String> call(final Subscriber<? super String> subscriber) {
return new Subscriber<String>(subscriber) {
@Override
public void onCompleted() {
if (!subscriber.isUnsubscribed()) {
subscriber.onCompleted();
}
}
@Override
public void onError(Throwable t) {
if (!subscriber.isUnsubscribed()) {
subscriber.onError(t);
}
}
@Override
public void onNext(String item) {
if (!subscriber.isUnsubscribed()) {
final String result = item.replaceAll("[^A-Za-z0-9]", "");
subscriber.onNext(result);
}
}
};
}
}

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package com.baeldung.rxjava.operator;
import rx.Observable;
import rx.Observable.Transformer;
public class ToLength implements Transformer<String, Integer> {
public static ToLength toLength() {
return new ToLength();
}
private ToLength() {
super();
}
@Override
public Observable<Integer> call(Observable<String> source) {
return source.map(String::length);
}
}

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package com.baeldung.rxjava;
import static org.junit.Assert.assertEquals;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import org.junit.Test;
import hu.akarnokd.rxjava2.async.AsyncObservable;
import io.reactivex.Observable;
public class AsyncAndSyncToObservableIntegrationTest {
AtomicInteger counter = new AtomicInteger();
Callable<Integer> callable = () -> counter.incrementAndGet();
/* Method will execute every time it gets subscribed*/
@Test
public void givenSyncMethod_whenConvertedWithFromCallable_thenReturnObservable() {
Observable<Integer> source = Observable.fromCallable(callable);
for (int i = 1; i < 5; i++) {
source.test()
.awaitDone(5, TimeUnit.SECONDS)
.assertResult(i);
assertEquals(i, counter.get());
}
}
/* Method will execute only once and cache its result.*/
@Test
public void givenSyncMethod_whenConvertedWithStart_thenReturnObservable() {
Observable<Integer> source = AsyncObservable.start(callable);
for (int i = 1; i < 5; i++) {
source.test()
.awaitDone(5, TimeUnit.SECONDS)
.assertResult(1);
assertEquals(1, counter.get());
}
}
/* Method will execute only once and cache its result.*/
@Test
public void givenAsyncMethod_whenConvertedWithFromFuture_thenRetrunObservble() {
ExecutorService executor = Executors.newSingleThreadExecutor();
Future<Integer> future = executor.submit(callable);
Observable<Integer> source = Observable.fromFuture(future);
for (int i = 1; i < 5; i++) {
source.test()
.awaitDone(5, TimeUnit.SECONDS)
.assertResult(1);
assertEquals(1, counter.get());
}
executor.shutdown();
}
/* Method will execute every time it gets subscribed*/
@Test
public void givenAsyncMethod_whenConvertedWithStartFuture_thenRetrunObservble() {
ExecutorService executor = Executors.newSingleThreadExecutor();
Observable<Integer> source = AsyncObservable.startFuture(() -> executor.submit(callable));
for (int i = 1; i < 5; i++) {
source.test()
.awaitDone(5, TimeUnit.SECONDS)
.assertResult(i);
assertEquals(i, counter.get());
}
executor.shutdown();
}
/*Method will execute only once and cache its result.*/
@Test
public void givenAsyncMethod_whenConvertedWithDeferFuture_thenRetrunObservble() {
List<Integer> list = Arrays.asList(new Integer[] { counter.incrementAndGet(), counter.incrementAndGet(), counter.incrementAndGet() });
ExecutorService exec = Executors.newSingleThreadExecutor();
Callable<Observable<Integer>> callable = () -> Observable.fromIterable(list);
Observable<Integer> source = AsyncObservable.deferFuture(() -> exec.submit(callable));
for (int i = 1; i < 4; i++) {
source.test()
.awaitDone(5, TimeUnit.SECONDS)
.assertResult(1, 2, 3);
}
exec.shutdown();
}
}

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package com.baeldung.rxjava;
import org.junit.Test;
import rx.Observable;
import rx.Observable.Operator;
import rx.Observable.Transformer;
import rx.Subscriber;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import static com.baeldung.rxjava.operator.ToCleanString.toCleanString;
import static com.baeldung.rxjava.operator.ToLength.toLength;
import static org.hamcrest.Matchers.hasItems;
import static org.hamcrest.Matchers.hasSize;
import static org.hamcrest.Matchers.notNullValue;
import static org.junit.Assert.assertThat;
public class RxJavaCustomOperatorUnitTest {
@Test
public void whenUseCleanStringOperator_thenSuccess() {
final List<String> list = Arrays.asList("john_1", "tom-3");
final List<String> results = new ArrayList<>();
final Observable<String> observable = Observable.from(list)
.lift(toCleanString());
// when
observable.subscribe(results::add);
// then
assertThat(results, notNullValue());
assertThat(results, hasSize(2));
assertThat(results, hasItems("john1", "tom3"));
}
@Test
public void whenUseToLengthOperator_thenSuccess() {
final List<String> list = Arrays.asList("john", "tom");
final List<Integer> results = new ArrayList<>();
final Observable<Integer> observable = Observable.from(list)
.compose(toLength());
// when
observable.subscribe(results::add);
// then
assertThat(results, notNullValue());
assertThat(results, hasSize(2));
assertThat(results, hasItems(4, 3));
}
@Test
public void whenUseFunctionOperator_thenSuccess() {
final Operator<String, String> cleanStringFn = subscriber -> new Subscriber<String>(subscriber) {
@Override
public void onCompleted() {
if (!subscriber.isUnsubscribed()) {
subscriber.onCompleted();
}
}
@Override
public void onError(Throwable t) {
if (!subscriber.isUnsubscribed()) {
subscriber.onError(t);
}
}
@Override
public void onNext(String str) {
if (!subscriber.isUnsubscribed()) {
final String result = str.replaceAll("[^A-Za-z0-9]", "");
subscriber.onNext(result);
}
}
};
final List<String> results = new ArrayList<>();
Observable.from(Arrays.asList("ap_p-l@e", "or-an?ge"))
.lift(cleanStringFn)
.subscribe(results::add);
assertThat(results, notNullValue());
assertThat(results, hasSize(2));
assertThat(results, hasItems("apple", "orange"));
}
@Test
public void whenUseFunctionTransformer_thenSuccess() {
final Transformer<String, Integer> toLengthFn = source -> source.map(String::length);
final List<Integer> results = new ArrayList<>();
Observable.from(Arrays.asList("apple", "orange"))
.compose(toLengthFn)
.subscribe(results::add);
assertThat(results, notNullValue());
assertThat(results, hasSize(2));
assertThat(results, hasItems(5, 6));
}
}

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package com.baeldung.rxjava;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;
import rx.Observable;
import rx.Observer;
import rx.exceptions.OnErrorNotImplementedException;
import rx.schedulers.Schedulers;
import rx.schedulers.Timestamped;
import java.util.concurrent.TimeUnit;
import static com.jayway.awaitility.Awaitility.await;
import static org.junit.Assert.assertTrue;
public class UtilityOperatorsIntegrationTest {
private int emittedTotal = 0;
private int receivedTotal = 0;
private String result = "";
@Rule
public ExpectedException thrown = ExpectedException.none();
@Test
public void givenObservable_whenObserveOnAfterOnNext_thenEmitsEventsOnComputeScheduler() throws InterruptedException {
Observable.range(1, 5)
.map(i -> i * 100)
.doOnNext(i -> {
emittedTotal += i;
System.out.println("Emitting " + i
+ " on thread " + Thread.currentThread().getName());
})
.observeOn(Schedulers.computation())
.map(i -> i * 10)
.subscribe(i -> {
receivedTotal += i;
System.out.println("Received " + i + " on thread "
+ Thread.currentThread().getName());
});
await().until(() -> {
assertTrue(emittedTotal == 1500);
assertTrue(receivedTotal == 15000);
}
);
}
@Test
public void givenObservable_whenObserveOnBeforeOnNext_thenEmitsEventsOnComputeScheduler() throws InterruptedException {
Observable.range(1, 5)
.map(i -> i * 100)
.observeOn(Schedulers.computation())
.doOnNext(i -> {
emittedTotal += i;
System.out.println("Emitting " + i
+ " on thread " + Thread.currentThread().getName());
})
.map(i -> i * 10)
.subscribe(i -> {
receivedTotal += i;
System.out.println("Received " + i + " on thread "
+ Thread.currentThread().getName());
});
await().until(() -> {
assertTrue(emittedTotal == 1500);
assertTrue(receivedTotal == 15000);
});
}
@Test
public void givenObservable_whenSubscribeOn_thenEmitsEventsOnComputeScheduler() throws InterruptedException {
Observable.range(1, 5)
.map(i -> i * 100)
.doOnNext(i -> {
emittedTotal += i;
System.out.println("Emitting " + i
+ " on thread " + Thread.currentThread().getName());
})
.subscribeOn(Schedulers.computation())
.map(i -> i * 10)
.subscribe(i -> {
receivedTotal += i;
System.out.println("Received " + i + " on thread "
+ Thread.currentThread().getName());
});
await().until(() -> {
assertTrue(emittedTotal == 1500);
assertTrue(receivedTotal == 15000);
});
}
@Test
public void givenObservableWithOneEvent_whenSingle_thenEmitEvent() {
Observable.range(1, 1)
.single()
.subscribe(i -> receivedTotal += i);
assertTrue(receivedTotal == 1);
}
@Test
public void givenObservableWithNoEvents_whenSingle_thenThrowException() {
Observable.range(1, 3)
.single()
.onErrorReturn(e -> receivedTotal += 10)
.subscribe();
assertTrue(receivedTotal == 10);
}
@Test
public void givenObservableWihNoEvents_whenSingleOrDefault_thenDefaultMessage() {
Observable.empty()
.singleOrDefault("Default")
.subscribe(i -> result += i);
assertTrue(result.equals("Default"));
}
@Test
public void givenObservableWithManyEvents_whenSingleOrDefault_thenThrowException() {
Observable.range(1, 3)
.singleOrDefault(5)
.onErrorReturn(e -> receivedTotal += 10)
.subscribe();
assertTrue(receivedTotal == 10);
}
@Test
public void givenObservable_whenDoOnNextAndDoOnCompleted_thenSumAllEventsAndShowMessage() {
Observable.range(1, 10)
.doOnNext(r -> receivedTotal += r)
.doOnCompleted(() -> result = "Completed")
.subscribe();
assertTrue(receivedTotal == 55);
assertTrue(result.equals("Completed"));
}
@Test
public void givenObservable_whenDoOnEachAndDoOnSubscribe_thenSumAllValuesAndShowMessage() {
Observable.range(1, 10)
.doOnEach(new Observer<Integer>() {
@Override
public void onCompleted() {
System.out.println("Complete");
}
@Override
public void onError(Throwable e) {
e.printStackTrace();
}
@Override
public void onNext(Integer value) {
receivedTotal += value;
}
})
.doOnSubscribe(() -> result = "Subscribed")
.subscribe();
assertTrue(receivedTotal == 55);
assertTrue(result.equals("Subscribed"));
}
@Test
public void givenObservable_whenDoOnErrorDoOnTerminateAndDoAfterTerminate_thenShowErrorTerminateAndAfterTerminateMessages() {
thrown.expect(OnErrorNotImplementedException.class);
Observable.empty()
.single()
.doOnError(throwable -> {
throw new RuntimeException("error");
})
.doOnTerminate(() -> result += "doOnTerminate")
.doAfterTerminate(() -> result += "_doAfterTerminate")
.subscribe();
assertTrue(result.equals("doOnTerminate_doAfterTerminate"));
}
@Test
public void givenObservable_whenTimestamp_thenEventsShouldAppearTimestamped() {
Observable.range(1, 10)
.timestamp()
.map(o -> result = o.getClass().toString())
.last()
.subscribe();
assertTrue(result.equals("class rx.schedulers.Timestamped"));
}
@Test
public void givenObservables_whenDelay_thenEventsStartAppearAfterATime() throws InterruptedException {
Observable<Timestamped<Long>> source = Observable.interval(1, TimeUnit.SECONDS)
.take(5)
.timestamp();
Observable<Timestamped<Long>> delay = source.delaySubscription(2, TimeUnit.SECONDS);
source.<Long>subscribe(
value -> System.out.println("source :" + value),
t -> System.out.println("source error"),
() -> System.out.println("source completed"));
delay.subscribe(
value -> System.out.println("delay : " + value),
t -> System.out.println("delay error"),
() -> System.out.println("delay completed"));
//Thread.sleep(8000);
}
@Test
public void givenObservable_whenRepeat_thenSumNumbersThreeTimes() {
Observable.range(1, 3)
.repeat(3)
.subscribe(i -> receivedTotal += i);
assertTrue(receivedTotal == 18);
}
@Test
public void givenObservable_whenUsing_thenReturnCreatedResource() {
Observable<Character> values = Observable.using(
() -> "resource",
r -> Observable.create(o -> {
for (Character c : r.toCharArray()) {
o.onNext(c);
}
o.onCompleted();
}),
r -> System.out.println("Disposed: " + r)
);
values.subscribe(
v -> result += v,
e -> result += e
);
assertTrue(result.equals("resource"));
}
@Test
public void givenObservableCached_whenSubscribesWith2Actions_thenEmitsCachedValues() {
Observable<Integer> source =
Observable.<Integer>create(subscriber -> {
System.out.println("Create");
subscriber.onNext(receivedTotal += 5);
subscriber.onCompleted();
}
).cache();
source.subscribe(i -> {
System.out.println("element 1");
receivedTotal += 1;
});
source.subscribe(i -> {
System.out.println("element 2");
receivedTotal += 2;
});
assertTrue(receivedTotal == 8);
}
}

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package com.baeldung.rxjava.operators;
import org.junit.Test;
import rx.Observable;
import rx.observers.TestSubscriber;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
public class RxAggregateOperatorsUnitTest {
@Test
public void givenTwoObservable_whenConcatenatingThem_thenSuccessfull() {
// given
List<Integer> listOne = Arrays.asList(1, 2, 3, 4);
Observable<Integer> observableOne = Observable.from(listOne);
List<Integer> listTwo = Arrays.asList(5, 6, 7, 8);
Observable<Integer> observableTwo = Observable.from(listTwo);
TestSubscriber<Integer> subscriber = TestSubscriber.create();
// when
Observable<Integer> concatObservable = observableOne.concatWith(observableTwo);
concatObservable.subscribe(subscriber);
// then
subscriber.assertCompleted();
subscriber.assertNoErrors();
subscriber.assertValueCount(8);
subscriber.assertValues(1, 2, 3, 4, 5, 6, 7, 8);
}
@Test
public void givenObservable_whenCounting_thenObtainingNumberOfElements() {
// given
List<String> lettersList = Arrays.asList("A", "B", "C", "D", "E", "F", "G");
TestSubscriber<Integer> subscriber = TestSubscriber.create();
// when
Observable<Integer> sourceObservable = Observable.from(lettersList)
.count();
sourceObservable.subscribe(subscriber);
// then
subscriber.assertCompleted();
subscriber.assertNoErrors();
subscriber.assertValueCount(1);
subscriber.assertValue(7);
}
@Test
public void givenObservable_whenReducing_thenObtainingInvertedConcatenatedString() {
// given
List<String> list = Arrays.asList("A", "B", "C", "D", "E", "F", "G");
TestSubscriber<String> subscriber = TestSubscriber.create();
// when
Observable<String> reduceObservable = Observable.from(list)
.reduce((letter1, letter2) -> letter2 + letter1);
reduceObservable.subscribe(subscriber);
// then
subscriber.assertCompleted();
subscriber.assertNoErrors();
subscriber.assertValueCount(1);
subscriber.assertValue("GFEDCBA");
}
@Test
public void givenObservable_whenCollecting_thenObtainingASet() {
// given
List<String> list = Arrays.asList("A", "B", "C", "B", "B", "A", "D");
TestSubscriber<HashSet> subscriber = TestSubscriber.create();
// when
Observable<HashSet<String>> reduceListObservable = Observable.from(list)
.collect(HashSet::new, HashSet::add);
reduceListObservable.subscribe(subscriber);
// then
subscriber.assertCompleted();
subscriber.assertNoErrors();
subscriber.assertValueCount(1);
subscriber.assertValues(new HashSet<>(list));
}
@Test
public void givenObservable_whenUsingToList_thenObtainedAList() {
// given
Observable<Integer> sourceObservable = Observable.range(1, 5);
TestSubscriber<List> subscriber = TestSubscriber.create();
// when
Observable<List<Integer>> listObservable = sourceObservable.toList();
listObservable.subscribe(subscriber);
// then
subscriber.assertCompleted();
subscriber.assertNoErrors();
subscriber.assertValueCount(1);
subscriber.assertValue(Arrays.asList(1, 2, 3, 4, 5));
}
@Test
public void givenObservable_whenUsingToSortedList_thenObtainedASortedList() {
// given
Observable<Integer> sourceObservable = Observable.range(10, 5);
TestSubscriber<List> subscriber = TestSubscriber.create();
// when
Observable<List<Integer>> listObservable = sourceObservable.toSortedList();
listObservable.subscribe(subscriber);
// then
subscriber.assertCompleted();
subscriber.assertNoErrors();
subscriber.assertValueCount(1);
subscriber.assertValue(Arrays.asList(10, 11, 12, 13, 14));
}
@Test
public void givenObservable_whenUsingToSortedListWithComparator_thenObtainedAnInverseSortedList() {
// given
Observable<Integer> sourceObservable = Observable.range(10, 5);
TestSubscriber<List> subscriber = TestSubscriber.create();
// when
Observable<List<Integer>> listObservable = sourceObservable.toSortedList((int1, int2) -> int2 - int1);
listObservable.subscribe(subscriber);
// then
subscriber.assertCompleted();
subscriber.assertNoErrors();
subscriber.assertValueCount(1);
subscriber.assertValue(Arrays.asList(14, 13, 12, 11, 10));
}
@Test
public void givenObservable_whenUsingToMap_thenObtainedAMap() {
// given
Observable<Book> bookObservable = Observable
.just(
new Book("The North Water", 2016),
new Book("Origin", 2017),
new Book("Sleeping Beauties", 2017));
TestSubscriber<Map> subscriber = TestSubscriber.create();
// when
Observable<Map<String, Integer>> mapObservable = bookObservable
.toMap(Book::getTitle, Book::getYear, HashMap::new);
mapObservable.subscribe(subscriber);
// then
subscriber.assertCompleted();
subscriber.assertNoErrors();
subscriber.assertValueCount(1);
subscriber.assertValue(new HashMap() {
{
put("The North Water", 2016);
put("Origin", 2017);
put("Sleeping Beauties", 2017);
}
});
}
@Test
public void givenObservable_whenUsingToMultiMap_thenObtainedAMultiMap() {
// given
Observable<Book> bookObservable = Observable
.just(
new Book("The North Water", 2016),
new Book("Origin", 2017),
new Book("Sleeping Beauties", 2017));
TestSubscriber<Map> subscriber = TestSubscriber.create();
// when
Observable multiMapObservable = bookObservable
.toMultimap(Book::getYear, Book::getTitle, () -> new HashMap<>(), (key) -> new ArrayList<>());
multiMapObservable.subscribe(subscriber);
// then
subscriber.assertCompleted();
subscriber.assertNoErrors();
subscriber.assertValueCount(1);
subscriber.assertValue(new HashMap() {
{
put(2016, Arrays.asList("The North Water"));
put(2017, Arrays.asList("Origin", "Sleeping Beauties"));
}
});
}
class Book {
private String title;
private Integer year;
public Book(String title, Integer year) {
this.title = title;
this.year = year;
}
public String getTitle() {
return title;
}
public Integer getYear() {
return year;
}
}
}

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package com.baeldung.rxjava.operators;
import io.reactivex.Observable;
import io.reactivex.schedulers.TestScheduler;
import org.junit.Test;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.TimeUnit;
import static org.hamcrest.CoreMatchers.hasItems;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertThat;
public class RxFlatmapAndSwitchmapUnitTest {
@Test
public void givenObservable_whenFlatmap_shouldAssertAllItemsReturned() {
//given
List<String> actualOutput = new ArrayList<>();
final TestScheduler scheduler = new TestScheduler();
final List<String> keywordToSearch = Arrays.asList("b", "bo", "boo", "book", "books");
//when
Observable.fromIterable(keywordToSearch)
.flatMap(s -> Observable
.just(s + " FirstResult", s + " SecondResult")
.delay(10, TimeUnit.SECONDS, scheduler))
.toList()
.doOnSuccess(s -> actualOutput.addAll(s))
.subscribe();
scheduler.advanceTimeBy(1, TimeUnit.MINUTES);
//then
assertThat(actualOutput, hasItems("b FirstResult", "b SecondResult",
"boo FirstResult", "boo SecondResult",
"bo FirstResult", "bo SecondResult",
"book FirstResult", "book SecondResult",
"books FirstResult", "books SecondResult"));
}
@Test
public void givenObservable_whenSwitchmap_shouldAssertLatestItemReturned() {
//given
List<String> actualOutput = new ArrayList<>();
final TestScheduler scheduler = new TestScheduler();
final List<String> keywordToSearch = Arrays.asList("b", "bo", "boo", "book", "books");
//when
Observable.fromIterable(keywordToSearch)
.switchMap(s -> Observable
.just(s + " FirstResult", s + " SecondResult")
.delay(10, TimeUnit.SECONDS, scheduler))
.toList()
.doOnSuccess(s -> actualOutput.addAll(s))
.subscribe();
scheduler.advanceTimeBy(1, TimeUnit.MINUTES);
//then
assertEquals(2, actualOutput.size());
assertThat(actualOutput, hasItems("books FirstResult", "books SecondResult"));
}
}

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package com.baeldung.rxjava.operators;
import org.junit.Test;
import rx.Observable;
import rx.observables.MathObservable;
import rx.observers.TestSubscriber;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
public class RxMathematicalOperatorsUnitTest {
@Test
public void givenRangeNumericObservable_whenCalculatingAverage_ThenSuccessfull() {
// given
Observable<Integer> sourceObservable = Observable.range(1, 20);
TestSubscriber<Integer> subscriber = TestSubscriber.create();
// when
MathObservable.averageInteger(sourceObservable)
.subscribe(subscriber);
// then
subscriber.assertCompleted();
subscriber.assertNoErrors();
subscriber.assertValueCount(1);
subscriber.assertValue(10);
}
@Test
public void givenRangeNumericObservable_whenCalculatingSum_ThenSuccessfull() {
// given
Observable<Integer> sourceObservable = Observable.range(1, 20);
TestSubscriber<Integer> subscriber = TestSubscriber.create();
// when
MathObservable.sumInteger(sourceObservable)
.subscribe(subscriber);
// then
subscriber.assertCompleted();
subscriber.assertNoErrors();
subscriber.assertValueCount(1);
subscriber.assertValue(210);
}
@Test
public void givenRangeNumericObservable_whenCalculatingMax_ThenSuccessfullObtainingMaxValue() {
// given
Observable<Integer> sourceObservable = Observable.range(1, 20);
TestSubscriber<Integer> subscriber = TestSubscriber.create();
// when
MathObservable.max(sourceObservable)
.subscribe(subscriber);
// then
subscriber.assertCompleted();
subscriber.assertNoErrors();
subscriber.assertValueCount(1);
subscriber.assertValue(20);
}
@Test
public void givenRangeNumericObservable_whenCalculatingMin_ThenSuccessfullObtainingMinValue() {
// given
Observable<Integer> sourceObservable = Observable.range(1, 20);
TestSubscriber<Integer> subscriber = TestSubscriber.create();
// when
MathObservable.min(sourceObservable)
.subscribe(subscriber);
// then
subscriber.assertCompleted();
subscriber.assertNoErrors();
subscriber.assertValueCount(1);
subscriber.assertValue(1);
}
@Test
public void givenItemObservable_whenCalculatingMaxWithComparator_ThenSuccessfullObtainingMaxItem() {
// given
Item five = new Item(5);
List<Item> list = Arrays.asList(new Item(1), new Item(2), new Item(3), new Item(4), five);
Observable<Item> itemObservable = Observable.from(list);
TestSubscriber<Item> subscriber = TestSubscriber.create();
// when
MathObservable.from(itemObservable)
.max(Comparator.comparing(Item::getId))
.subscribe(subscriber);
// then
subscriber.assertCompleted();
subscriber.assertNoErrors();
subscriber.assertValueCount(1);
subscriber.assertValue(five);
}
@Test
public void givenItemObservable_whenCalculatingMinWithComparator_ThenSuccessfullObtainingMinItem() {
// given
Item one = new Item(1);
List<Item> list = Arrays.asList(one, new Item(2), new Item(3), new Item(4), new Item(5));
TestSubscriber<Item> subscriber = TestSubscriber.create();
Observable<Item> itemObservable = Observable.from(list);
// when
MathObservable.from(itemObservable)
.min(Comparator.comparing(Item::getId))
.subscribe(subscriber);
// then
subscriber.assertCompleted();
subscriber.assertNoErrors();
subscriber.assertValueCount(1);
subscriber.assertValue(one);
}
class Item {
private Integer id;
public Item(Integer id) {
this.id = id;
}
public Integer getId() {
return id;
}
}
}