I've spent a lot of time fixing bugs and cleaning up the tests, and now it's finally time to add some more functionality. The smallest step I can think of right now is to add a button to the view that closes it.
To get the full picture clear in my mind I have another look at the types I have in action.
First I would like the test to start the application and open the view, just like the other tests. Then I would like the test to (1) trigger a click on the close button, which is done by calling a method on the SongsViewFake. Since I don't want any logic inside the view, the view should just pass on the request by (2) raising an event in the ISongsView interface. Whoever listens to that notification, in this case Thingy, should (3) tell the view to close itself.
Now it's clear to me that the test should look like this.
[Test] public void Songs_window_closes_when_clicking_close_button() { Application .Start(view => { view.ClickCloseButton(); Assert.That(view.HasBeenClosed, Is.True); }); }It's quite similar to the other tests. This is a bit cleaner in the sense that I can do the assertion inside the showAction and not have to use variables in the test to keep track of the state.
I extend the fake with the ClickCloseButton() method and the HasBeenClosed property.
public class SongsViewFake : ISongsView { public event Action OnCloseButtonClick; public bool HasBeenClosed { get; private set; } // ... public SongsViewFake(Action<SongsViewFake> showAction) { ShowAction = showAction; HasBeenClosed = false; } public void CloseView() { HasBeenClosed = true; } public void ClickCloseButton() { OnCloseButtonClick.Raise(); } // ... }I also add the CloseView() method that I expect the production code to call to tell the view to close itself. The code compiles, so I run the tests. The result is something I recognize by now:
There are no subscribers to the OnCloseButtonClick event.
So according to my initial thoughts, I continue to extend the ISongsView interface with the OnCloseButtonClick event and the CloseView() method. In order for the code to compile I also have to implement these in SongsView.
public interface ISongsView { event Action OnCloseButtonClick; event Action OnViewClosed; void ShowView(); void CloseView(); } public partial class SongsView : Form, ISongsView { public event Action OnCloseButtonClick; // ... public void CloseView() { Close(); } private void CloseButtonClick( object sender, EventArgs e) { OnCloseButtonClick.Raise(); } }The code compiles, but still shows the same failure message when running the tests. The smallest step I can take is to start listening to the event with an empty handler, so that's what I do.
public class Thingy : ApplicationContext { // ... public void ShowView() { View.OnViewClosed += () => CloseAction( this ); View.OnCloseButtonClick += () => { }; View.ShowView(); } }And I get the failure I expect.
And the solution is to change the event handler.
public class Thingy : ApplicationContext { // ... public void ShowView() { View.OnViewClosed += () => CloseAction( this ); View.OnCloseButtonClick += View.CloseView; View.ShowView(); } }One line of code, and I'm done. When the event is raised, call the CloseView() method on View. This solution works, the tests are all green.
This test was a bit different than the previous tests in that the interesting part of the use case is started with that an event is triggered inside a fake. The normal way of thinking about tests is that the test tells the code to perform something. It's a bit mind twisting when the test just fires an event, hoping that someone should take care of it. But it's something you get used to.
Running the application, clicking the close button works great.
I check in my code.