fork and clone this repository and open it in VS Code
run npm install
run npm run watch or start the watch Task in VS Code
start the debugger
To create vsix extension:
install vsce with npm install -g vsce
run vsce package
You should now see a second VS Code window, the Extension Development Host.
Open a folder in this window and click the "Test" icon in the Activity bar.
Now you should see the fake example test suite in the side panel: