Add coverage report and basic vitest settings

Set tests folder and coverage settings, update run commands for tests

ReadMe.md

@@ -141,6 +141,18 @@ vitest is used for all usage tests
 npx vitest
 ```
 
+for one stop tests
+
+```sh
+npm run test:run
+```
+
+To show the full coverate (of all files)
+
+```sh
+npm run test:coverage
+```
+
 Currently covered:
 
 - FormatBytes