PowerMock whenNew without @PrepareForTest?

Question

This is my situation, I have 2 very simple classes:

public class B {

    public void doSomething(){
        System.out.println("doSomething B reached");
    }
}

And:

public class A {

public void doSomething(){
    B b = new B();
    b.doSomething();
    System.out.println("doSomething A reached");
}

}

I want to test method doSomething of class A with Mockito. Therefor, I want to mock an instance of class B and give this to A when it is instantiating class B. I don't want b.doSomething() to be reached at all, for isolation reasons.

I know I can reach this behaviour by creating the following unittest:

@RunWith(PowerMockRunner.class)
public class TestA {

    @Test
    @PrepareForTest(A.class)
    public void testDoSomethingOfA() throws Exception{
        A a = PowerMockito.spy(new A());
        B b = PowerMockito.mock(B.class);
        PowerMockito.whenNew(B.class).withNoArguments().thenReturn(b);
        a.doSomething();
    }
}

which results in output:

doSomething A reached

So this work! However, my problem now is that we use the Jococo plugin for test coverage. Jococo doesn't cover code tested with the @PrepareForTest(A.class) statement. And my company values accurate code testing coverage.

My question: Is there another way around to give A an instantiation of B without having to use the @PrepareForTest statement?

Many thanks in advance!

Answer 1

To answer my own question, yes, use an agent: https://github.com/jayway/powermock/wiki/PowerMockAgent

Answer 2

@Rens Groenveld: After integrating PowerMockAgent, did you make any changes in your test class or source code ? I tried integrating PowerMockAgent and removed my main source class from @PrepareForTest but the behavior is same (creating new instance instead of mock).

I have tried jacoco offline instruments and many other solution, It did not work.

I can not post to your comment (needs 50 points) hence added as answer.