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I've hit a bit of a roadblock, and I'm hoping someone can help!

I've written a metro application that serves as a unit test runner, and I now need to be able to call this application headlessly so that it can be used for validation in the build process. The way the metro app works is it runs a bunch of unit tests, generates an XML file that contains the test results, and displays the results to the user.

Ideally, I would have a simple script that would run the metro app, execute the tests, exit the app, and then have the ability to read the results in the generated XML file. Is this possible, and if so, what's the best way to do it?

Here are some more specific questions:

  1. How can one start a metro app headlessly, and in the metro app is there a way to detect this so that it does not wait for user input?

  2. Is it possible to access files within the package of a metro app from an outside process?

EDIT - A workaround would be to create a custom Visual Studio test runner and then find a way to run the tests automatically with each build. I know this can be done within the IDE, but I'm not sure if there's a way to do this with a script.

Jeff
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3 Answers3

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I imagine you've long since moved past this problem, but for the sake of anyone else looking to do this, I got it to work without too much hassle. To execute a Metro app in an automated/headless fashion, I wrote a simple desktop command-line utility that takes the name of a metro app and makes use of the IApplicationActivationManager interface to launch it. I can then call that utility from a script.

The second argument to that inteface's ActivateApplication method is a string that gets passed in to the activated app, kind of like command-line arguments. It shows up as the Arguments property of the LaunchActivatedEventArgs that is received by the app's OnLaunched handler. The default implementation of OnLaunched in the Visual Studio template projects passes this value to the MainPage when it first navigates to it, where it comes through into the OnNavigatedTo handler as the Parameter property of the NavigationEventArgs. You could catch it in whichever place is more convenient.

My launcher utility passes a hard-coded flag through there, as well as forwarding its own command-line arguments. That allows the top-level script to pass arbitrary data down into the Metro app. The app can use that data to realize that it's running headless and run its tests. It can spit out whatever kind of result data you like into one of its folders (like its LocalFolder), which a desktop app can then read from %LOCALAPPDATA%\Packages\APPNAME\LocalState. I setup my launcher utility to wait for the result files to appear after launching the app, and then use them to determine its own exit code. The launcher utility can't kill the app afterward, but the app can kill itself when it's done via CoreApplication.Exit.

That setup worked great for a while, but a problem that I'm running into now is that the app isn't always launched to the foreground, and the runtime will suspend/terminate the app after it hasn't been the foreground app for some amount of time (currently ~10-15 seconds). So any tests that take too long won't work with this approach, barring some workaround that I haven't discovered yet (which I was searching for when I came across this question).

Jayonas
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I doubt you'll be able to do it.

It's the same sort of problem as trying to run a WPF app headlessly, but harder since you'd also have to deal with the Metro sandbox security model.

P.S. Happy to be proven wrong!

Richard Banks
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No, sorry. You hit a wall with your first requirement of a script that runs the Metro application in "headless" mode in the first place. Your second requirement would be your next wall. One application cannot see, let alone monitor, another application/thread/process. Then your third requirement is also impossible. Files inside an application are isolated. It sounds to me like you found a good candidate for a desktop app. Having said that, don't mistakenly think that you can't have a companion Metro application that is your dashboard. It's just the execution core can't be hosted inside the WinRT sandbox.

Jerry Nixon
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