MSTest code coverage

I have a test project for a web service and, when I run tests in debug mode, everything works ok. However, when I just run tests, I get following error, for a referenced assembly that I try to obtain code coverage:

Class Initialization method WebServiceTest.wstest.MyClassInitialize threw exception. System.IO.FileLoadException: System.IO.FileLoadException: Could not load file or assembly 'TestAssembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=57f286581e1d278a' or one of its dependencies. Strong name validation failed. (Exception from HRESULT: 0x8013141A) ---> System.Security.SecurityException: Strong name validation failed. (Exception from HRESULT: 0x8013141A). Everything I found said to register TestAssembly in GAC. Is this what should I do? Why is it working in debug mode? Thank you

I had the same problem, and the link below helped me...

http://weblogs.asp.net/soever/archive/2005/07/23/420338.aspx

VS.NET 2005: Code coverage for signed assemblies I am currently working on an application using VS.NET 2005, and because all the TDD tools like unit testing and code coverage are available I started to use them.

When I started code coverage on my signed application I got the following exception:

Test method X threw exception: System.IO.FileLoadException: Could not load file or assembly 'Y, Version=1.0.0.0, Culture=neutral, PublicKeyToken=Z' or one of its dependencies. HRESULT: 0x8013141A Strong name validation failed. ---> System.Security.SecurityException: Exception from HRESULT: 0x8013141A Strong name validation failed at X.

Not so strange if you think about it. Assembly is signed, code coverage needs code instrumentation, means modifications of the assembly, resulting in incorrect assembly so the validation failed.

Solution is to resign the assembly after instrumentation.

If you open the localtestrun.testrunconfig file (or something similar) in your solution items (double-click it), you can enable resigning in the Code Coverage section. This solves the problem.