Rewrite of fs mock logic

[fussel178]

Rewrite of fs mock logic for more complex data structures.

[pklaschka]

Could you please clarify:

In which cases does this break?

[fussel178]

For example, you can mock a specific directory and add files to the directory, but then you should also mock the files, so that the function readFileSync can read these files. If you don't do this, then you have an inconsistency between the folder definition and the actual file existence.
So, when you mock a specific directory with different files in it, then these files are for example empty, but readable and existent.
(This can also happens to links and directories in directories.)

[pklaschka]

Perfect, thanks for the clarification 🙏.