tl;dr: If unit tests referencing Crystal Reports are crashing, find the app.config for the test runner for your version of Visual Studio and ensure it has the following:
<startup useLegacyV2RuntimeActivationPolicy="true">
</startup>
I’ve been using Visual Studio 2015 at home for a while and decided to install it at on my work machine several months ago. All of the projects I tried it on didn’t have any problems with one exception. One solution used Crystal Reports to generate PDFs and had a unit test that generated a PDF as part of the test. That test worked fine in Visual Studio 2013 but would cause the test runner to crash in Visual Studio 2015. If I ran the tests with the debugger, I would see the famous error below.
The website that used this code worked fine. It was only the unit tests that would fail and only in Visual Studio 2015. While researching the problem, I found several references stating that adding useLegacyV2RuntimeActivationPolicy="true" would fix the problem. I added it to the app.config for the test project, but it didn’t solve the problem. After wasting too much time on it, I decided to let it go for the time being and stick with Visual Studio 2013.
When Microsoft released the update for Visual Studio 2015 on November 30th, I decided to try again. I was hoping the problem was due to something going wrong when I had installed Crystal Reports and hoped the update installation would work some magic. And of course, no joy. I then tried uninstalling Crystal Reports and installing the newer version that had come out since. Still no joy.
Then I finally started actually thinking (tends to help a lot). All of the fixes that I was finding for this problem were in regards to WPF or WinForm apps. My problem was with a unit test project. I knew that the app.config in the project was used by the generated assembly since I could refer to it in the tests. But the unit test project generates a DLL, not an EXE. Isn’t there supposed to be an EXE that actually runs the tests?
When I added unit test as keywords in my googling, I found this question on StackOverflow. Aha! Visual Studio 2015 is in the Microsoft Visual Studio 14.0 folder, so I followed the path from there and found…several configuration files for vstest.executionengine.exe. Ok, fine, let’s check ‘em all. They all actually had the correct setting except for one, so I updated that one, ran my tests and…AARGH! Still not working. OK, time to start thinking again. I thought I remembered seeing something in the output window, and sure enough, there was the filename of the test runner right under my nose. So I found C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE\CommonExtensions\Microsoft\TestWindow\TE.ProcessHost.ManagedExe.exe.config, added the <startup/> section, and tried again. Success!
So I’m finally up and running with Visual Studio 2015 and Crystal Reports. And I’m still waiting for a better alternative to Crystal Reports so I can get away from the Crystal Reports hell.