java - Stubbing action listener with spock

Question

I have this in my presenter:

private void init() {
    view.subscribeOnButtonClick(new Clickable() {
        @Override
        public void clickPerformed() { sortArray(); }
    });
}

And I want to remember this clickable object in my test to trigger it in 'when' part (to simulate button click)

I tried like this:

def view = Mock(ArraySorterView)
def clickable
view.subscribeOnButtonClick(_) >> { x -> clickable = x }
when:
clickable.clickPerformed()

But it is not working. What am I doing wrong?