Test Discovery throws BadImageFormatException

[rickardgranberg]

We have a solution with mixed C# and C++ projects. Unit testing of C++ is done with mstest, but it appears that the xunit test runner/discoverer is not prepared to find a C++ dll, as the attempt to load it as an assembly throws a BadImageFormatException:

[xUnit.net 00:00:00.2870680] Exception discovering tests from Library.UnitTest.Cpp: System.BadImageFormatException: Could not load file or assembly 'Library.UnitTest.Cpp.dll' or one of its dependencies. An attempt was made to load a program with an incorrect format.
File name: 'Library.UnitTest.Cpp.dll' ---> System.BadImageFormatException: An attempt was made to load a program with an incorrect format. (Exception from HRESULT: 0x8007000B)

at System.Reflection.AssemblyName.nGetFileInformation(String s)
at System.Reflection.AssemblyName.GetAssemblyName(String assemblyFile)
at Xunit.Sdk.ReflectionAssemblyInfo..ctor(String assemblyFileName)$$RethrowMarker$$ at ExceptionExtensions.RethrowWithNoStackTraceLoss(Exception ex)
at Xunit.RemoteAppDomainManager.CreateObjectTObject
at Xunit.Xunit2Discoverer..ctor(ISourceInformationProvider sourceInformationProvider, IAssemblyInfo assemblyInfo, String assemblyFileName, String xunitExecutionAssemblyPath, String configFileName, Boolean shadowCopy, String shadowCopyFolder, IMessageSink diagnosticMessageSink)
at Xunit.Xunit2Discoverer..ctor(ISourceInformationProvider sourceInformationProvider, String assemblyFileName, String configFileName, Boolean shadowCopy, String shadowCopyFolder, IMessageSink diagnosticMessageSink)
at Xunit.Xunit2..ctor(ISourceInformationProvider sourceInformationProvider, String assemblyFileName, String configFileName, Boolean shadowCopy, String shadowCopyFolder, IMessageSink diagnosticMessageSink)
at Xunit.XunitFrontController.CreateInnerController()
at Xunit.XunitFrontController.get_InnerController()
at Xunit.XunitFrontController.get_TargetFramework()
at Xunit.Runner.VisualStudio.TestAdapter.VsTestRunner.DiscoverTestsTVisitor

[bradwilson]

This is expected behavior. We log all exceptions that happen during discovery. Since you are not expecting xUnit.net to run this assembly, you can safely ignore this exception.

[rickardgranberg]

I have no problem ignoring this exception. The TFS build (which also runs the tests) does however, as this exception leads to a "Partially Succeeded" build. I'm currently investigating using the option in our .runsettings file, but I'm not sure if I want to enable this as it may suppress other errors. Is there a way to suppress specific exceptions?

[bradwilson]

We could log it with a different level than Error. I presume that's what the issue is.

visualstudio.xunit/xunit.runner.visualstudio.testadapter/VsTestRunner.cs

Lines 159 to 163 in 83ea70d

	catch (Exception e)
	{
	logger.SendMessage(TestMessageLevel.Error,
	String.Format("[xUnit.net {0}] Exception discovering tests: {1}", stopwatch.Elapsed, e.Unwrap()));
	}

[bradwilson]

And also:

visualstudio.xunit/xunit.runner.visualstudio.testadapter/VsTestRunner.cs

Lines 152 to 154 in 83ea70d

	else
	logger.SendMessage(TestMessageLevel.Error,
	String.Format("[xUnit.net {0}] Exception discovering tests from {1}: {2}", stopwatch.Elapsed, fileName, ex));

[rickardgranberg]

Yes, that would make TFS (and me) happy :)