jMock custom actions, doAll expectation and onConsecutiveCalls

I had an issue with a class that I've not encountered before with projects on which I use jMock: I have a mocked class whose method modifies an object it takes as a parameter.  I suspect this is due to poor coupling in the application, but I'll refactor at a later date -- for now I welcome the challenge as an opportunity to explore three aspects of jMock with which I'm unfamiliar: custom actions, doAll and onConsecutiveCalls.

Problem

public class WillBeMocked {
    public Object processBusinessObject businessObject) {
        ReturnObject returnObject = new ReturnObject(businessObject);

        // change state of input parameter
        businessObject.incrementCounter();

        return returnObject;
    }
}

Solution

create custom jmock.org.api.Action in my test class

private static class BusinessObjectIncrementCounterAction<T> implements org.jmock.api.Action

{

    private final BusinessObject businessObjectInstance;

    public BusinessObjectIncrementCounterAction(final BusinessObject businessObjectInstance)

    {

        this. businessObjectInstance = businessObjectInstance;

    }

    @Override

    public void describeTo(final Description description)

    {

        description.appendText("calls incrementCounter() on the businessObjectInstance");

    }

    @Override

    public Object invoke(final Invocation invocation) throws Throwable

    {

        businessObjectInstance.incrementCounter();

        return null;

    }

}

create static call to construct custom Action in my test class

private static <T> org.jmock.api.Action incrementCounter(final BusinessObject businessObjectInstance)

{

    return new BusinessObjectIncrementCounterAction <T>(businessObjectInstance);

}

use doAll to execute custom Action and mocked class's method call

                

context.checking(new Expectations() {

    {

        oneOf(willBeMockedInstance).process(businessObjectInstance);

        will(doAll(incrementCounter(businessObjectInstance), 

             returnValue(new ReturnObject("A"))));

    }

});

use onConsecutiveCall to 

context.checking(new Expectations() {

    {

        exactly(2).of(willBeMockedInstance).process(businessObjectInstance);

        will(onConsecutiveCalls(doAll(incrementCounter(businessObjectInstance), 

             returnValue(new ReturnObject("A")))),

             doAll(incrementCounter(businessObjectInstance), 

             returnValue(new ReturnObject("B")))));

    }

});