Mocking simple property access with JMockIt

Question

I have a simple get-set interface:

public interface Foo {

    void setBaz(String baz);
    String getProcessedBaz();    
}

This interface is a dependency of my actual class under test. I'm trying to mock out Foo to have this effective behavior:

public class MockedFoo implements Foo {

    private String bazField;

    @Override
    public void setBaz(String baz) {
        bazField = baz;
    }

    @Override
    public String getProcessedBaz() {
        return "PROCESSED_" + bazField;
    }
}

So my expected result is:

mockedFoo.setBaz("ABC");
assertEquals("PROCESSED_ABC", mockedFoo.getProcessedBaz());

I was able to capture the method argument using withCapture in a Verification, but how do I set up an Expectation with that same input value? It seems you can do either one or the other.

Is there a way to express this in JMockIt? I'm using the latest version (1.9).

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NOTE: I'm aware that I can simply set up a Mockup<Foo> instance and put in all the code above. However, my real code is much more complex and I would prefer not to hand-craft the entire mock class.

Answer 1

NOTE: This was inspired by Varun's answer, but I wanted to avoid using reflection and intermediate classes. Rogério also provided a viable alternative, but it did not fit into the overall structure of my test. Thanks to both!

---

Here's how I finally got it working:

public interface Foo {
    void setBaz(String baz);
    String getProcessedBaz();
}

@RunWith(JMockit.class)
public class FooTest {
    @Injectable
    private Foo mockedFoo = null;

    @Test
    public void testBaz() { 
        new Expectations() {
            private String bazState; // Variable inside Expectations stores the state between calls

            {
                mockedFoo.setBaz(anyString);
                result = new Delegate() {
                    void setBaz(String baz) { bazState = baz; }
                };

                mockedFoo.getProcessedBaz();
                result = new Delegate() {
                    String getProcessedBaz() { return "PROCESSED_" + bazState; }
                };
            }
        };

        mockedFoo.setBaz("ABC");
        assertEquals("PROCESSED_ABC", mockedFoo.getProcessedBaz());
    }
}