Test Your XAML-based Windows Store Apps with Visual Studio 2013 Benjamin Day

Transcription

1 Test Your XAML-based Windows Store Apps with Visual Studio 2013 Benjamin Day Level: Intermediate

2 Benjamin Day Brookline, MA Consultant, Coach, & Trainer Microsoft MVP for Visual Studio ALM Team Foundation Server, Software Testing, Scrum, Software Architecture Scrum.org Classes Professional Scrum Developer (PSD) Professional Scrum Foundations (PSF)

3 Online courses at Pluralsight.com

4 Agenda Unit Testing for Windows Store Apps Design for Testability in Model-View-ViewModel Coded UI Testing for Windows Store Apps

5 Testing and software architecture are closely related.

6 If you don t think of how you ll test your app before you build it

7 life will be difficult.

8 Your app. Let s say you have a Windows Store App Calls back to some service endpoints The services write data in to a database You re probably writing all this at the same time Feels like you re writing one application.

9 Client-side & Server-side: They re 2 applications Service Service-Oriented Application (SOA) Uses a database for it s persistence Domain Model implementation User interface is a collection of endpoints (REST, WebAPI) Client Runs on a desktop machine Windows Store Has it s own object model Uses services for persistence

10 Why do I think this? When data is returned via service, you re leaving the AppDomain Objects on the server are converted to XML XML is hierarchical When you re writing service-oriented applications, it s a mistake to think that you re returning objects. Your application is actually message-oriented

11 Why do I think this? Difficult to share code on both sides of the wire You re writing both apps at the same time but the server-side code doesn t need the client code. The client definitely needs the service code.

12 Benefits of thinking about 2 apps It s like building a tunnel under a mountain. Meet in the middle Design the endpoints Server team works on server code Client team works on client code Find problems faster Iterate with your customer faster

13 Benefits of thinking about 2 apps Code to abstractions Fewer dependencies Loosely coupled Easier to test

14 Unit Testing

15 Disclaimer: I m obsessed with unit testing.

16 What s a unit test? Little chunks of code that exercise other chunks of code and verify the results. Unit Test Project(s) System Under Test (Domain Models, Presentation, Data Access, Services, etc.)

17 Why unit test? What s done stays done. You find problems early. Bugs stay dead. Refactoring is painless. If your application is large, it s tough to know when you ve broken something obscure. Unit tests tell you when you ve broken your app.

18 Unit Tests vs. Integration Tests Unit Tests Tests small units of functionality in isolation Dependencies are typically not tested Integration Tests Tests larger pieces of functionality Might test the whole application Usually requires deployment

19 What do I test? Windows Store ViewModels Operations Commands INotifyPropertyChanged Progress Bars Show/Hide Logic Login/Logout Domain Models Domain Model Services Service logic I don t test making service calls from the app to the services Utility methods Server-side Data access code aka. Repositories Domain Model Domain Model Services Services Direct calls to the controllers (Rarely) Calls via HTTP

20 Benefits of 2 applications + unit testing Thinking of 2 apps helps isolate problems Are the service unit tests passing? Are the WinStore App unit tests passing? WinStore App Tests Passing? Services Passing? Conclusion Yes No Service problem No Yes WinStore App problem Yes Yes New problem No No Whew! $%^& is broken.

21 Tip: Don t write new code if the tests are broken. Always code on top of a known good state If you make changes and the tests stop passing, it s your fault. Do your team a favor. Please, don t check in.

22 The layers in an app. User Interface (Windows Store) Coded UI tests Presentation (Model-View-ViewModel) Domain Model / Service Layer Repository / Data Access Unit tests The Service (REST, WebAPI, etc.)

23 Layers help you with Separation of Concerns

24 It can be challenging to separate the UI from the code behind the UI.

25 Model-View-ViewModel helps you keep the UI separated from the code that drives the UI.

26 Model-View-ViewModel = MVVM

27 MVVM is an abstraction of what the UI is thinking and doing.

28 How does MVVM help you design for testability?

29 User Interfaces are hard to test.

30 MVVM lets you test the UI without the actual UI.

31 All that stuff that you d put in the code behind goes in the ViewModel.

32 Demo: Tasks, Async, Await, & Unit Tests

33 Things that help. Modeling selections SingleSelectListViewModel MultiSelectListViewModel Wrapping fields ViewModelField<T> Testers for Progress Bar logic Testers for INotifyPropertyChanged

34 Coded UI Tests

35 What is a Coded UI Test?

36 How is a Coded UI Test different from a Unit Test?

37 Demo: Testing Logic.

38 Demo: Testing gestures.

39 Any last questions?

40 Thanks.