Is there a bug in the preview feature?
It’s possible that this is a potential issue. I noticed that some developers also get the same error, see this Github thread: Unable to connect to testing platform runner process when using testing platform server mode.
I did some tests on my side, changing the project file, using the MSTest and the Xunit test, restarting VS, checking/unchecking the preview feature, but failed to reproduce this issue.
I doubt that this issue appears in some specific situations.
I suggest you follow up that Github ticket, add comments and wait for the latest update.
Thanks for helping us make Visual Studio better.
Have a great day!
Tianyu
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