java-tutorials/rxjava-2/src/test/java/com/baeldung/rxjava/CompletableUnitTest.java

package com.baeldung.rxjava;

import io.reactivex.Completable;
import io.reactivex.Flowable;
import io.reactivex.Single;
import io.reactivex.observers.DisposableCompletableObserver;
import org.junit.Before;
import org.junit.Test;

public class CompletableUnitTest {

    Completable first;
    Completable second;
    Completable error;
    Throwable throwable = new RuntimeException();

    @Before
    public void setUpCompletables() {
        first = Completable.fromSingle(Single.just(1));
        second = Completable.fromRunnable(() -> {});
        error = Single.error(throwable)
          .ignoreElement();
    }

    @Test
    public void whenCompletableConstructed_thenCompletedSuccessfully() {
        Completable completed = Completable.complete();
        completed.subscribe(new DisposableCompletableObserver() {
            @Override
            public void onComplete() {
                System.out.println("Completed!");
            }

            @Override
            public void onError(Throwable e) {
                e.printStackTrace();
            }
        });
        Flowable<String> flowable = Flowable.just("request received", "user logged in");
        Completable flowableCompletable = Completable.fromPublisher(flowable);
        Completable singleCompletable = Single.just(1)
          .ignoreElement();

        completed.andThen(flowableCompletable)
          .andThen(singleCompletable)
          .test()
          .assertComplete();
    }

    @Test
    public void whenCombiningCompletables_thenCompletedSuccessfully() {
        first.andThen(second)
          .test()
          .assertComplete();
    }

    @Test
    public void whenCombinedWithError_thenCompletedWithError() {
        first.andThen(second)
          .andThen(error)
          .test()
          .assertError(throwable);
    }

    @Test
    public void whenCombinedWithNever_thenDoesNotComplete() {
        first.andThen(second)
          .andThen(Completable.never())
          .test()
          .assertNotComplete();
    }

    @Test
    public void whenMergedCompletables_thenCompletedSuccessfully() {
        Completable.mergeArray(first, second)
          .test()
          .assertComplete();
    }

    @Test
    public void whenMergedWithError_thenCompletedWithError() {
        Completable.mergeArray(first, second, error)
          .test()
          .assertError(throwable);
    }

    @Test
    public void whenFlatMaped_thenCompletedSuccessfully() {
        Completable allElementsCompletable = Flowable.just("request received", "user logged in")
          .flatMapCompletable(message -> Completable
              .fromRunnable(() -> System.out.println(message))
          );
        allElementsCompletable
          .test()
          .assertComplete();
    }

    @Test
    public void whenAmbWithNever_thenCompletedSuccessfully() {
        Completable.ambArray(first, Completable.never(), second)
          .test()
          .assertComplete();
    }

    @Test
    public void whenAmbWithError_thenCompletedWithError() {
        Completable.ambArray(error, first, second)
          .test()
          .assertError(throwable);
    }

}