Getting started with Windows Phone 7 and unit test

Getting started with Tests on your WP7 App

Friday, June 29, 2012

http://share.dotnetlombardia.org/events/120628/_Layouts/listform.aspx?PageType=4&ListId=%7BDB9BFCA1-E5E7-4F38-915B-1939ACE9B1C7%7D&ID=9






Who am I?

• Developer freelance:–C# Asp.net Mvc, Wpf, Wp7–Python Django–Blog: orangecode.it/blog


What we’re going to see



•What is a unit test



•What is a unit test• How to write it



•What is a unit test• How to write it• Integration Test vs Unit Test



•What is a unit test• How to write it• Integration Test vs Unit Test• Testing tools for WP7



•What is a unit test• How to write it• Integration Test vs Unit Test• Testing tools for WP7• The first test



•What is a unit test• How to write it• Integration Test vs Unit Test• Testing tools for WP7• The first test• Maintaining test suite


Let’s start


From Wikipedia

• A unit test is a piece of a code (usually a method) that invokes another piece of code and checks the correctness of some assumptions afterward. • If the assumptions turn out to be wrong, the unit test has failed. • A “unit” is a method or function.


Good test properties• It should be automated and repeatable. • It should be easy to implement. • Once it’s written, it should remain for future use. • Anyone should be able to run it. • It should run at the push of a button. • It should run quickly.

Roy Osherove


Good test properties

• If your test doesn’t follow at least one of the previous rules, there’s a high probability that what you’re implementing isn’t a unit test.

• You’ve done integration testing.


Integration Test

• Integration testing means testing two or more dependent software modules as a group.


First Test

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Unit vs Integration Test

• integration test: test many units of code that work together to evaluate one or more expected results from the software.

• unit test: test only a single unit in isolation.

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Classic wp7 approach

• Code coupled with UI– Xaml + Code Behind -> one class

public partial class MainView : PhoneApplicationPage { public MainView() { InitializeComponent(); } }

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Classic wp7 approach

Your code is NOT TESTABLE!

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•Architectural Pattern•Derived from Presentation Model pattern (Fowler)

•Clear separation between UI and Logic

MVVM Approach

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UI

Collections, DelegateCommand, Properties

ViewModel


MVVM Approach• Code structure:

–ViewModel (c#): Logic–View (Xaml): Presentation–No more code behind

• Now the ViewModel (as a plain c# class) IS TESTABLE

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Unit Test framework

• Nunit for Windows Phone 7

• No official mocking framework for Windows Phone 7, but I found out that Moq 3.1 for silverlight works!

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Test Runner

• NUnit

• Resharper

• Test Driven.net

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Context

• Application that resize images• Two boxes for the new size• Ok button

• Error if the image is not in 4:3

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Solution structure

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WP7 App

ViewModel

WP7 Class Library

NUnit Library (via NuGet)

TestSuite

View


MainViewModel

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namespace OrangeCode.Resizer.ViewModel{ public class MainViewModel { public int Height { get; set; }

public int Width { get; set; }

public bool RatioCheck { get { return Width*3 == Height*4; } } }}


First test

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namespace OrangeCode.Resizer.Fixture{ public class MainViewModelFixture { [Test] public void RatioCheck_InvalidSize_ReturnFalse() {

var viewModel= new MainViewModel();

viewModel.Height = 100; viewModel.Width = 80;

bool result= viewModel.RatioCheck;

Assert.IsFalse(result); } }}


First test

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[Test]public void RatioCheck_InvalidSize_ReturnFalse(){

var viewModel= new MainViewModel();

viewModel.Height = 100;viewModel.Width = 80;

bool result = viewModel.RatioCheck;

Assert.IsFalse(result);}

[MethodName]_[StateUnderTest]_[ExpectedBehavior]

Arrange objects.

Act on an objects.

Assert something expected.


Run test

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Refactor our test

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[TestFixture] public class MainViewModelFixture { private MainViewModel viewModel;

[SetUp] public void SetUp() { viewModel = new MainViewModel(); }

[Test] public void RatioCheck_InvalidSize_ReturnFalse() { viewModel.Height = 100; viewModel.Width = 80;

Assert.IsFalse(viewModel.RatioCheck); } }

executed before every test


Refactor our test

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[TestFixture] public class MainViewModelFixture { [Test] public void RatioCheck_InvalidSize_ReturnFalse() { viewModel.Height = 100; viewModel.Width = 80;

Assert.IsFalse(viewModel.RatioCheck); }

[TearDown]public void TearDown(){

viewModel=null;}

}

executed after every test


Run test again

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Some more cases

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[TestCase(10,10)] [TestCase(12, 12)] [TestCase(0, 0)] public void RatioCheck_InvalidSize_ReturnFalse(int height,int width) { viewModel.Height = height; viewModel.Width = width;



Some more cases

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From red to green

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namespace OrangeCode.Resizer.ViewModel{ public class MainViewModel { public int Height { get; set; }

public int Width { get; set; }

public bool RatioCheck { get {

if(Width>0 && Height>0)return Width*3 == Height*4;

return false; }

} }}


Run tests

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Test Driven Development

• We just made it!

• Life Cycle:–Write test (red) –Write logic to pass the test (green)–Refactor code (refactor)–Again..

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Back to the first test

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[TestCase(10,10)] [TestCase(12, 12)] [TestCase(0, 0)] public void RatioCheck_InvalidSize_ReturnFalse(int height,int width) { viewModel.Height = height; viewModel.Width = width;



Good test properties• It should be automated and repeatable. • It should be easy to implement. • Once it’s written, it should remain for future

use. • Anyone should be able to run it. • It should run at the push of a button. • It should run quickly.

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What to test in WP7

• Properties with logic (not only get/set)• Command• Navigation between pages• Interaction with storage• Converter• Event

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Final thoughts

• Use small consistent test –One test can test only one feature

• If work with legacy code–create an integration test for every feature–split a integration test in few unit test

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Recap

•What is a unit test• How to write it• Integration Test vs Unit Test • Testing tools• The first test• Maintaining test suite

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Be in contactMail: [email protected]: @piccoloaiutanteWeb: www.orangecode.itBlog: www.orangecode.it/blogGitHub: https://github.com/piccoloaiutante

Community: WEBdeBS

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mailto:[email protected]

mailto:[email protected]

http://www.orangecode.it

http://www.orangecode.it

http://www.orangecode.it/blog

http://www.orangecode.it/blog

https://github.com/piccoloaiutante

https://github.com/piccoloaiutante

Grazie aDotNET Lombardia!

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Technology

Getting started with Windows Phone 7 and unit test