JMockit: How to mock a method according to an argument given in the constructor?

Question

I want to mock the following class using JMockit:

public class A {

    private int n;

    public A(int n) {
        this.n = n;
    }

    public boolean isCorrect() {
        return n % 2 == 0;
    }
}

The class is initialized throughout my code, and I usually don't have access to that part of the code in my test.
At some of my tests I want to mock it so that if the class is initialized with the value of 3, 'isCorrect' will return true (which is not the normal behavior), and at some other tests I want to mock it so that 'isCorrect' will return false no matter how it was initialized.

I tried to find a way to do it in the documentation, but it wasn't so user-friendly and I gave up on it.

Answer 1

Thanks @assylias for you answer. I think I found a better way to implement the first mock, which combines the ideas from your first and second (after edit) answers. It goes like this:

new MockUp<A> () {

    private int n;

    @Mock
    public void $init(Invocation inv, int n) {
        this.n = n;
        inv.proceed();
    }

    @Mock
    public boolean isCorrect(Invocation inv) {
        if (n == 3) {
            return true;
        }
        return inv.proceed();
    }
};

Update

For the second mock (the brute false return), this will do:

new MockUp<A> () {

    @Mock
    public boolean isCorrect() {
        return false;
    }
};

And again, thanks to @assylias for helping me with this :)