CODEWITHSUNDEEP
javajunitcompletable-future
Nipul Sindwani
Nipul Sindwani

Reputation: 81

Why JUnit Does not finish when mocked a method call which returned CompletableFuture Object

public class A{
    @Autowired
    B b;
    public List<String> method1(){
        CompletableFuture<List<String>> completableFuture = b.getCompletableFutureList();
        // further processing 
        // returning a list of strings
        return completableFuture.get();
    }
}

@RunWith(MockitoJUnitRunner.class)
public class TestA{
    private A cut;
    @Mock B b;
    List<String> prepareStringList(){
        List<String> stringList = new ArrayList<>();
        stringList.add("Random String");
        return stringList;
    }
    CompletableFuture<List<String>> prepareCompletableStringList(){
        CompletableFuture<List<String>> completableFuture = new CompletableFuture<>();
        completableFuture.completedFuture(prepareStringList);
        return completableFuture;
    }

    @Test
    public void method1Test(){
         when(b.getCompletableFutureList()).thenReturn(prepareCompletableStringList);
       List<String> list = cut.method1();
       //verifications()
    }
  }

In this class I want to mock method call getCompletableFutureList() and Want to return a custom CompletableFutureObject. Please tell me whether I am completely wrong in my approach to this JUnit. because simply mocking CompletableFuture in my test class neither my test is failing nor it is passing. And If I am wrong What is the correct approach. My Junit also does not terminates.

Upvotes: 2

Views: 712

Answers (1)

Rigel Bezerra de Melo
Rigel Bezerra de Melo

Reputation: 111

CompletableFuture.completedFuture is a static method that returns a new completed CompletableFuture. What you want instead is CompletableFuture.complete, which will terminate the current CompletableFuture.

Upvotes: 1

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