How to mock Abstract class method in a class to be tested

Question

There is an abstract class

public abstract class BaseProcessor {
 public BooksTransaction getBooksTransaction() {
        return booksTransaction;
    }
}

There is another final class which is to be tested using Junit

public final class CreateOrganisationProcessor extends BaseProcessor {

public boolean process() throws Exception { //method to be tested
        request = new CreateOrganisationRequest(IntegrationSystems.valueOf(getBooksTransaction().getSource()),
                IntegrationSystems.valueOf(getBooksTransaction().getDestination()), getBooksTransaction()); 
        request.setRequestTypes(getRequestTypes());
return true;
}
}

I tried spying the BaseProcessor class and mocking getBooksTransaction method to return BooksTransaction Object. Code:

@Test
   public void testProcess() throws Exception {
BaseProcessor spy = Mockito.spy(new CreateOrganisationProcessor());
       BooksTransaction booksTransaction = new BooksTransaction();
       booksTransaction.setReferenceID(DEFAULT_REFERENCE_ID);
       Mockito.doReturn(booksTransaction).when(spy).getBooksTransaction();
}

Here, BooksTransaction is an JPA Entity class.

However, when I run the test case, the mock does not seem to be working, it does not return a BooksTransaction Object. It neither throws an exception , nor any error .

I would like to know the right way to spy this method so that it returns me an object of BooksTransaction as per my mock .

I am new to Mockito , any help would be appreciable. Thanks in advance.

Answer 1

It's funny that you got 5 up-votes for a question that does not even compile to begin with... I have simplified it just a bit, so that I could actually compile it, since I do not know your structure or can't even guess it correctly.

But the very first point you should be aware of is that Mockito can't by default mock final classes; you have a comment under your question that shows how to enable that.

@Getter
static abstract class BaseProcessor {
    private BooksTransaction BooksTransaction;
}

@Getter
static class CreateOrganisationProcessor extends BaseProcessor {

    CreateOrganisationRequest request;

    public boolean process() { //method to be tested
        request = new CreateOrganisationRequest(getBooksTransaction());
        return true;
    }

    public CreateOrganisationRequest getRequest() {
        return request;
    }
}


@RequiredArgsConstructor
@Getter
static class BooksTransaction {
    private final String testMe;
}

@Getter
@RequiredArgsConstructor
static class CreateOrganisationRequest {
    private final BooksTransaction booksTransaction;
}

And here is a test that does work:

@Test
public void test() {
    CreateOrganisationProcessor org = new CreateOrganisationProcessor();
    CreateOrganisationProcessor spy = Mockito.spy(org);
    System.out.println(spy);
    BooksTransaction booksTransaction = new BooksTransaction("go!");

    Mockito.doReturn(booksTransaction).when(spy).getBooksTransaction();

    spy.process();
    BooksTransaction mocked = spy.getRequest().getBooksTransaction();
    Assert.assertEquals(mocked.getTestMe(), "go!");
}

And now think about it, you say in a comment : //method to be tested but you are not even calling it in your test, sounds fishy doesn't it? Than that method is defined in CreateOrganisationProcessor , but you are assigning your spy to:

 BaseProcessor spy = Mockito.spy(new CreateOrganisationProcessor());

So now you can't even call process anymore on that spy reference, since it is not defined in BaseProcessor .