NUnit3TestAdapter errors when running xUnit tests

My .NET Core codebase has a mix of xUnit and NUnit tests which all get built into the same directory with something like:

dotnet build -o c:\some\shared\dir .\my.sln

When I try to run some xUnit tests with:

dotnet vstest c:\some\shared\dir\xunit-test.dll

…the tests pass but I see an error in the console:

Error initializing RunSettings. Default settings will be used
System.IO.FileNotFoundException: Could not load file or assembly 'System.Xml.XPath.XmlDocument, Version=4.0.2.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.
File name: 'System.Xml.XPath.XmlDocument, Version=4.0.2.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'
   at NUnit.VisualStudio.TestAdapter.AdapterSettings.Load(String settingsXml)
   at NUnit.VisualStudio.TestAdapter.NUnitTestAdapter.Initialize(IDiscoveryContext context, IMessageLogger messageLogger) in D:\repos\nunit\nunit3-vs-adapter\src\NUnitTestAdapter\NUnitTestAdapter.cs:line 126


Exception System.IO.FileNotFoundException, Exception thrown executing tests
Could not load file or assembly 'System.Xml.XPath.XmlDocument, Version=4.0.2.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.
   at NUnit.VisualStudio.TestAdapter.NUnit3TestExecutor.RunAssembly(String assemblyPath, TestFilter filter)
   at NUnit.VisualStudio.TestAdapter.NUnit3TestExecutor.RunTests(IEnumerable`1 sources, IRunContext runContext, IFrameworkHandle frameworkHandle) in D:\repos\nunit\nunit3-vs-adapter\src\NUnitTestAdapter\NUnit3TestExecutor.cs:line 99

It seems that NUnit’s test adapter is selected first and fails, so dotnet test moves on to the xUnit adapter, which runs the tests. Note that I don’t see this error if:

• I use dotnet publish instead of dotnet build (System.Xml.XPath.XmlDocument.dll is copied into the target directory)
• I use dotnet test instead of dotnet vstest

The error is similar to what’s described in #589, but the repro seems very different so I didn’t want to muddy that issue.

Environment

NUnit 3.11.0 NUnit3TestAdapter 3.11.0 .NET Core SDK 2.2.202 Windows 10.0.17763 (RS5)

Repro (from PowerShell)

mkdir ~\projects\xunit-nunit-clash
cd ~\projects\xunit-nunit-clash
dotnet new xunit -n xunit-test
dotnet new nunit -n nunit-test
dotnet build .\xunit-test\  -f netcoreapp2.2 -o ..\bin\
dotnet build .\nunit-test\  -f netcoreapp2.2 -o ..\bin\
dotnet vstest .\bin\xunit-test.dll

[damonbarry]

Noticed the release this morning…thanks!

[OsirisTerje]

Ahh… I see. I’m trying to get the dates correct, but I got a few days delayed here due to travels during the summer vacation. Normally a good time for releasing stuff, but not this year 😉

Hope it works for your production code 😃