How to set expectation to params passed to void methods using EasyMock

Question

I am using EasyMock and EasyMock CE 3.0 to mock dependent layers and test my classes. Below is the scenario for which I am not able to find any solution

I have class to be tested, which calls a dependent class void method that takes an input param, and alters the same param. The method that I am testing is doing some operations based on the altered param, which I have to test now for various scenarios

Consider the below sample, where I have tried to put the same scenario

public boolean voidCalling(){
    boolean status = false;
    SampleMainBean mainBean = new SampleMainBean();
    dependentMain.voidCalled(mainBean);
    if(mainBean.getName() != null){
        status = true; 
    }else{
        status = false;
    }
    return status;
}

And the dependentMain class the below method

public void voidCalled(SampleMainBean mainBean){
    mainBean.setName("Sathiesh");
}

To have full coverage, I need to have 2 test cases to test both the scenarios where true and false are returned, but I always get false as I am not able to set the behaviour of the void method to alter this input bean. How can I get a true as result in this scenario using EasyMock

Thanks in advance for any help.

score 7 · Accepted Answer · edited May 23 '17 at 12:23

Starting from the answer in this answer: EasyMock: Void Methods, you can use IAnswer.

// create the mock object
DependentMain dependentMain = EasyMock.createMock(DependentMain.class);

// register the expected method
dependentMain.voidCalled(mainBean);

// register the expectation settings: this will set the name 
// on the SampleMainBean instance passed to voidCalled
EasyMock.expectLastCall().andAnswer(new IAnswer<Object>() {
    @Override
    public Object answer() throws Throwable {
        ((SampleMainBean) EasyMock.getCurrentArguments()[0])
                .setName("Sathiesh");
        return null; // required to be null for a void method
    }
});

// rest of test here

score 2 · Answer 2 · answered Apr 14 '12 at 10:41

Thanks for your reply.. I got the problem resolved... :) Thanks for the sample code too.

Using the above code snippet, One change that I had to do is,

// register the expected method
dependentMain.voidCalled((SampleMainBean) EasyMock.anyObject());

With this am able to get the updated bean in the method to be tested.

Thanks again for your help.

How to set expectation to params passed to void methods using EasyMock

2 Answers2