GWT testing with mockito - gwt

Question

Simple Question:
Verification (1) passes.
Verification (2) does not. Why? How to fix it?
Test
#Test
public void test() {
System.out.println("test");
EventBus eb = mock(EventBus.class);
MyWidget.View v = mock(MyWidget.View.class);
GreetingServiceAsync s = mock(GreetingServiceAsync.class);
HasClickHandlers button = mock(HasClickHandlers.class);
when(v.getButton()).thenReturn(button);
new MyWidget(eb, v, s);
button.fireEvent(mock(ClickEvent.class));
verify(button).addClickHandler(any(ClickHandler.class)); (1)
verify(v).alert(anyString()); (2)
}
Widget
#Inject
public MyWidget(EventBus eventBus, View view, GreetingServiceAsync service){
this.view = view;
this.service = service;
bindView();
bindEventBus();
}
private void bindView(){
view.getButton().addClickHandler(new ClickHandler() {
#Override
public void onClick(ClickEvent event) {
view.alert("test");
}
});
}

Answer 1

because button is a mock, so calling fireEvent on it doesn't actually fire the event; and onClick is never called on the view.

Answer 2

Because Button was mocked out and there is no implementation telling it what to do when fireEvent is called. See the line:
HasClickHandlers button = mock(HasClickHandlers.class);
...
button.fireEvent(mock(ClickEvent.class));

Answer 3

As David Wallace said, you are mocking the button. It does lose all its abilities.
you could fix this by making a ArgumentCatptor
ArgumentCaptor<ClickHandler> captor = ArgumentCaptor.forClass(ClickHandler.class);
Then manually fire the function of the event by using:
captor.getValue().onClick(null);
This will fake the call that should have been made by the button.
If your class only has one button or one catcher for a specific event you can make it extend the ClickHandler class. Then you can just call the onClick of your class.

Answer 4

That is what I did:
public class ClickableElement implements HasClickHandlers{
ClickHandler ch;
#Override
public void fireEvent(GwtEvent<?> event) {
ch.onClick((ClickEvent) event);
}
#Override
public HandlerRegistration addClickHandler(ClickHandler handler) {
this.ch = handler;
return null;
}
};