dotnet watch process started by auto watch feature not stopped by dotnet-test-explorer.stop on windows

[allenbenz]

dotnet sdk: 6.0.100
nunit: 3.13.2
OS: windows 10
example repo: https://github.com/allenbenz/dotnet-test-explorer-linger-issue

The dotnet watch process isn't stopped when executing dotnet-test-explorer.stop. The cmd shell that started the dotnet watch process is closed however.

Workaround is to kill the dotnet process with task manager.

Reproduction steps:

1. Enable the auto watch feature
2. Open vscode in the checked out example repo (where the .sln file is)
3. Open task manager, observe respective dotnet and cmd entries
4. Run Stop running processes
5. Observe dotnet entries still present:
   • dotnet watch test --verbosity:quiet --logger "trx;LogFileName=C:\Users\allen\AppData\Local\Temp\test-explorer-fvHIQG\autoWatch0.trx"
   • "C:\Program Files\dotnet\dotnet.exe" "C:\Program Files\dotnet\sdk\6.0.100\DotnetTools\dotnet-watch\6.0.100-rtm.21527.8\tools\net6.0\any\dotnet-watch.dll" test --verbosity:quiet --logger trx;LogFileName=C:\Users\allen\AppData\Local\Temp\test-explorer-fvHIQG\autoWatch0.trx

[allenbenz]

Looking into this more, this is specific to windows.
https://serverfault.com/questions/47389/task-scheduler-only-killing-cmd-exe-but-not-its-child-processes
https://stackoverflow.com/questions/32705857/cant-kill-child-process-on-windows

I'm able to reproduce the issue by running
cmd /c "dotnet watch test --project dotnet-test-explorer.sln"
and manually terminating the cmd process.

Using taskkill /pid <cmd pid> /t /f does kill the dotnet child processes.

[allenbenz]

Dropping

              if (this.isWindows) {
                  child_process.exec('taskkill /pid ' + p.pid + ' /T /F')
              } else {
                  p.kill("SIGKILL");
              }

in the stop method fixes the dotnet-test-explorer.stop command.

Not sure what vscode does on close but it has the same problem and it's not killing the child processes either, but that's a separate issue.