VScode Error: Unable to get working directory for project Miscellaneous Files - file RunTestsHandler.cs line 124

Question

I am currently working with VSCode on Windows. I have one folder opened in my workspace which contains several projects. Since we build the projects for net8.0 AND net481, I use the setting "dotnet.preferCSharpExtension": true for my workspace. I have not changed any other settings (neither for user, workspace or folder). I have C# extension v2.39.29 installed.

In my test projects, which use MSTest, I can click the little buttons Run all tests/Debug all tests/Run test/Debug test and they work - i.e. after clicking them the projects needed for these tests are built, then the tests are run/debugged.

In order to nail down some issue, I wanted to make a copy of a given test project, then remove content subsequentially. So I copied the test project folder, put it in the main folder, gave it a new name. I can run the new test project with dotnet test. But when I click any of the little buttons Run all tests/Debug all tests/Run test/Debug test, I just get the output

Error: Unable to get working directory for project Miscellaneous Files - file RunTestsHandler.cs line 124

in my .NET Test log.

I already tried restarting the language server, closing and reopening VScode, restarting Windows, uninstalling and reinstalling C# Dev Kit. None helped.

What else can I do?

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I noticed that the colors in the code differ between the working test project (left) and the new non-working one (right). I can hover over the greenish text and get some popup. In the non-working one I have less greenish text. This indicates that something was not loaded.

Answer 1

I had to update my .sln file. After adding the new project to it and restarting language server, everything was loaded and worked.

See also github.