Test Impact Analysis

Article
06/09/2011

This is Syed Aslam Basha here from Relationship experience division (RXD) team.

Test impact analysis helps developers to quickly identify the tests(unit/CUIT) that need to be run for the latest code change. It’s one of the features in visual studio 2010 (VS) available in Premium and Ultimate editions. It works with only managed code.

Let me show Test impact analysis with a Sample web application which has a web page and a class along with Test project.

Launch visual studio 2010
Click on new project ->Visual C# - Test – Test Project ( make sure you have selected .NET Framework4 to see the test project)
Give appropriate project name and save the project
Close VS
Launch VS 2010
Click file-> New project - > Web -> select ASP.NET web application
Give appropriate project name and save the project
Right click and add new class and close the solution.
Open the test project and add the website. The solution will look like
Create a simple method in class file as DisplayText which returns string
Create unit test for the above method in UnitTest1.cs as
Launch test impact view by clicking on Test -> Windows - > Test impact view
If the test impact diagnostic data is not enabled, click on the link in test impact view window to enable it. Alternatively, you can also set it in test settings as below ( Test -> Edit test settings - > Data and diagnostics)
Now build the solution and run the unit test to baseline data
Click on Test-> Windows -> Test view
Select the test method and click on run
At this point the test impact view will look like
Now, lets change the code in DisplayText method and add line of code as
Since there is change in code it shows up in impacted tests as
Select the impacted test and click on run tests. Make sure the unit test passes to ensure the code change hasn’t effected the test case.