BAEL-2127 Chaining Completables in RxJava (#5323)

rxjava-2/pom.xml

@@ -38,9 +38,8 @@
 
     <properties>
         <assertj.version>3.8.0</assertj.version>
-        <rx.java2.version>2.1.3</rx.java2.version>
+        <rx.java2.version>2.2.2</rx.java2.version>
         <awaitility.version>1.7.0</awaitility.version>
         <rxrelay.version>2.0.0</rxrelay.version>
     </properties>
-
 </project>

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

@@ -0,0 +1,112 @@
+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);
+    }
+
+}