docs(faq): add documentation about directory cleanup

Author: hasezoey

docs/guides/faq.md

@@ -10,3 +10,8 @@ No, this package will **not** delete any binaries, so after an system upgrade th
 ### Why is there no documentation about class-options / interfaces in the documentation?
 
 It is recommended to directly look at the TSDoc for these properties to get their type & documentation
+
+### Do testing database paths get cleaned up?
+
+If the Database path is generated by this package, then it will automatically get cleaned up (ensured to run by process event `beforeExit`)  
+If the Database path is provided, then it will not be automatically cleaned up, cleanup needs to be called explicitly like `.cleanup(true)` (parameter is to force-delete the directory)