Thursday, February 14, 2013

Error when executing Unit Tests for Windows Store apps

When creating  unit tests for a Windows Store app,  the test runner always failed with the following error message:

------ Run test started ------

Creating a new clean layout...

Copying files: Total 4 mb to layout...

Registering the application to run from layout...

Deployment complete. Full package name: "2c5c99b8-8b5d-4ed3-8e1e-f638b2312c72_1.0.0.0_neutral__0c27qnas074n4"

Exception has been thrown by the target of an invocation.

========== Run test finished: 0 run (0:00:04,6740956) ==========

If we try to attach the debugger to see where it goes wrong, it also fails:



We tried some things but nothing helped. In the end we found the solution on Stackoverflow. It seems that this can be caused if you start changing some stuff(yes some stuff, no exact indication what can cause it and what not) in the App.xaml file.

In the StackOverflow answer they mention for example the following situations:

  • Application tag in app.xaml setting any properties (like RequestedTheme)
  • App.xaml referencing a ResourceDictionary which uses custom attached properties.

We were using the RequestedTheme property. After moving this property from the XAML file to the code behind our tests started to work.

Seems like a bug to me!

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