Write tests for findUniqueFilename() in UploadWorker.kt

[AlexG-2003]

Description

Look at PR #5877 for more details.

I have updated the method findUniqueFilename() in UploadWorker.kt to improve its efficiency in finding a unique name, fixing #2506. I don't have time to write tests for it at the moment so if someone would like to write tests for it that would be appreciated.

Tests should insure that the file name is changed as expected (appended with a three digit hash in the form #XXX) and that the file name is indeed unique.

[angrezichatterbox]

I would like to work on this issue :)

[Kota-Jagadeesh]

@nicolas-raoul I spoke with @angrezichatterbox, and he mentioned that he won’t be working on this anymore as he’s busy with other projects. I checked with him before assigning this to myself, and he had no objections, so I’m assigning it to myself 🙂