Mockito refuses to throw checked exception

Question

I'm using Mockito for my unit tests and I encounetered a problem with throwing exception on spied object. I have done this before on this object (in different test case and it worked). Here's the test code:

@Test
public void callInitiated_FsmInitializationException() throws FsmInitializationException, Exception {
    MocSbb moc = Mockito.spy(testObj);

    MocTracer tracer = Mockito.mock(MocTracer.class);
    Mockito.doReturn(tracer).when(moc).getTracer();

    CAP2InitialDPArg idp = Mockito.mock(CAP2InitialDPArg.class);
    MocFsm mocFsm = Mockito.mock(MocFsm.class);
    //Mockito.doReturn(mocFsm).when(moc).getSs7Fsm();

    TicketingLocalInterface ticketing = mockTicketingLocalInterface();
    CAP2InitialDPArgWrap idpWrap = Mockito.mock(CAP2InitialDPArgWrap.class);
    PowerMockito.whenNew(CAP2InitialDPArgWrap.class).withArguments(idp, tracer).thenReturn(idpWrap);

    MocSession mocSession = Mockito.mock(MocSession.class);
    Mockito.doReturn(mocSession).when(moc).getMocSession();

    Mockito.when(moc.getSs7Fsm()).thenThrow(new FsmInitializationException()); ////HERE'S THE PROBLEM

    moc.callInitiated(idp);

    verify(moc).getFailedFsm();
} 

here's the method on which the exception should be thrown:

protected MocFsm getSs7Fsm() throws FsmInitializationException {
    mocFsm.setContextProvider(getMocLocalObject());
    return mocFsm;
}  

the error I get during test execution looks like this:

Testcase: callInitiated_FsmInitializationException(com.nsn.as.ccs.moc.sbb.MocSbbTest):  Caused an ERROR

Checked exception is invalid for this method!
Invalid: com.nsn.as.ccs.moc.fsm.FsmInitializationException
org.mockito.exceptions.base.MockitoException: 
Checked exception is invalid for this method!
Invalid: com.nsn.as.ccs.moc.fsm.FsmInitializationException
at com.nsn.as.ccs.moc.sbb.MocSbbTest.callInitiated_FsmInitializationException(MocSbbTest.java:1194)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.runTestMethod(PowerMockJUnit44RunnerDelegateImpl.java:322)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.executeTest(PowerMockJUnit44RunnerDelegateImpl.java:309)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTestInSuper(PowerMockJUnit47RunnerDelegateImpl.java:112)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTest(PowerMockJUnit47RunnerDelegateImpl.java:73)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.runBeforesThenTestThenAfters(PowerMockJUnit44RunnerDelegateImpl.java:297)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.invokeTestMethod(PowerMockJUnit44RunnerDelegateImpl.java:222)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.runMethods(PowerMockJUnit44RunnerDelegateImpl.java:161)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$1.run(PowerMockJUnit44RunnerDelegateImpl.java:135)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.run(PowerMockJUnit44RunnerDelegateImpl.java:133)
at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.run(JUnit4TestSuiteChunkerImpl.java:112)
at org.powermock.modules.junit4.common.internal.impl.AbstractCommonPowerMockRunner.run(AbstractCommonPowerMockRunner.java:57)  

Does anyone have any idea why it doesn't work in this case?

Answer 1

Following this answer. Using Mockito's doAnswer instead of thenThrow method solved my issue.

Mockito.doAnswer(
      invocation -> {
        throw new Exception("Something went wrong");
      })
  .when(moc)
  .getSs7Fsm();

I know it's too late but just in case anyone faces the same issue.

Answer 2

I have finally found the solution for this problem.

We have used an anonymous class extending original Sbb class which was tested and in this extended class implementation of mentioned method was altered and throws expression was removed which caused the problem.

I should have read my colleagues code more carefully.