Mock with Mockito return a InvocationTargetException

Question

I'm writing some unit test and I stumble accross this strange "bug" which prevent me from running my unit test.

When I run the "when(...).thenReturn(...)", I receive a InvocationTargetException. Then strange things is that when I debug, it goes into the real object and crash on a null member. When I debug other "when", it goes in a function called "Intercept" which prevent to go in the real code... I don't understand what is different with this object and how to prevent this weird behavior.

Here is my unit test:

@Test
public void getSyncStatusShouldReturnValueFromDiskWhenNotRunning() throws IOException {
    //Arrange
    when(updater.isDone()).thenReturn(true);
    when(brandSyncUpdater.isDone()).thenReturn(true); //This is where it throw error
    when(stationSyncUpdater.isDone()).thenReturn(true);

    //Act
    //Assert
}

Here is my setUp() and member section of my unit class test

private Updater updater;
private BrandSyncUpdater brandSyncUpdater;
private StationSyncUpdater stationSyncUpdater;

@Before
public void setUp() {
    updater = mock(Updater.class);
    brandSyncUpdater = mock(BrandSyncUpdater.class);
    stationSyncUpdater = mock(StationSyncUpdater.class);
}

I don't know if it's related but the BrandSyncUpdater and StationSyncUpdater both have a parent called SyncUpdater where the isDone() function is located.

EDIT

Hierarchy of class

Updater is a class on its own

BrandSyncUpdater and StationSyncUpdater are extending SyncUpdater

Updater isDone() signature and code:

public boolean isDone() {
    return states.isEmpty();
}

SyncUpdater isDone() signature and code:

public boolean isDone() {
    return currentStates.isEmpty();
}

EDIT 2

Here is the stack traces of the error in the console. You'll notice that the error here is a "NullPointerException" because it try to use the variable currentStates. But when debugging, the error thrown by mockito is InvocationTargetException.

java.lang.NullPointerException
    at com.stingray360.clap.synchronizer.contentcontroller.queue.SyncUpdater.isDone(SyncUpdater.java:117)
    at com.stingray360.clap.synchronizer.contentcontroller.queue.BrandSyncUpdater.isDone(BrandSyncUpdater.java:15)
    at com.stingray360.clap.synchronizer.contentcontroller.SyncDispatcherTest.getSyncStatusShouldReturnValueFromDiskWhenNotRunning(SyncDispatcherTest.java:190)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at org.junit.internal.runners.TestMethod.invoke(TestMethod.java:68)

could you post the `BrandSyncUpdater` and `Updater` classes? — Ruben, Oct 19 '15 at 16:11
I can't since it's code from my job but if you tell me the things you want to know, I can post some parts or/and add information to my question. Like I said, Updater is working ok, it's the BrandSyncUpdater and StationSyncUpdater that throw the error when mocked. — Jean-François Côté, Oct 19 '15 at 16:25
Signature of methods and hierarchy of classes would be helpful — Ruben, Oct 19 '15 at 16:59
Are you sure the class/method is not final? What is the exact and complete stack trace of the exception? — JB Nizet, Oct 19 '15 at 17:39
@JBNizet that was my first thought, but, if it were final, he would have got a `MissingMethodInvocationException` instead of an `InvocationTargetException`. Sorry @Jean-François Côté, I have no idea. — Ruben, Oct 19 '15 at 17:56

score 4 · Accepted Answer · answered Oct 19 '15 at 18:07

4

I just found the problem by error trying something else.

My SyncUpdater class wasn't public (it was package). So when trying to use Reflection, it got stuck and throw this weird error.

Thanks for the help of people in the comments!

answered Oct 19 '15 at 18:07

Jean-François Côté

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Like I said, my class wasn't public, it was package access. As soon as I put the "public" back, it started to work. – Jean-François Côté Apr 06 '16 at 12:01

score 1 · Answer 2 · answered Feb 10 '23 at 09:33

1

I was able to fix the same issue by adding the following code snippet to the test Class.

@ObjectFactory
public IObjectFactory getObjectFactory() {
    return new PowerMockObjectFactory();
}

answered Feb 10 '23 at 09:33

Dinithi

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Barani r · Answer 3 · 2017-11-13T10:50:07.167

0

I also got this error. In my case i missed @RunWith(PowerMockRunner.class) for my Class (i know it is silly mistake, but wasted few hours troubleshooting everything else :) ).

@RunWith(PowerMockRunner.class)
public class SimpleServiceUpgradeManagerTestNotUsed {
//Class content

}

edited Nov 13 '17 at 10:50

answered Nov 13 '17 at 08:52

Barani r

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score 0 · Answer 4 · answered Sep 11 '18 at 01:59

0

I also met this kind of exception, the reason is I didn't initialize the class to which the method I mocked belongs.

answered Sep 11 '18 at 01:59

Simin Wen

1

Vikki · Answer 5 · 2020-01-13T14:40:42.263

0

I encountered the same problem with codes below

catch (final HttpStatusCodeException e)

After I remove the final before HttpStatusCodeException, the Junit test works fine.

And I just use Mockito, no PowerMock

edited Jan 13 '20 at 14:40

answered Jan 13 '20 at 09:31

Vikki

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Mock with Mockito return a InvocationTargetException

5 Answers5