Continuing the theme of testing with gwtmockito, I’d like to show you a neat class that’s bundled with gwtmockito that allows for easy mocking of GWT-RPC asynchronous services.

The class I’m talking about is AsyncAnswers. It’s meant to be used with the doAnswer stubber.

Supposing we have a LoginServiceAsync class:

public interface LoginServiceAsync {
    void login(String login, String password, AsyncCallback<SomePojo> callback);
}

Assuming service is a mock for LoginServiceAsync, we could simulate a successful trip to the server with:

gwteventbinder and gwtmockito are great projects that are esential if you’re writing applications in Google Web Toolkit/GWT. So it was a surprise to me that they don’t play together well “out of the box”.

See, the problem is that gwtmockito injects it’s own (safe, not using any code that requires running a browser) mocks when it encounters GWT.create in your code. That’s very cool, but when using gwteventbinder, you need to call the bindEventHandlers method to, well, bind the event handler. And the mock, obviously, doesn’t do that.