Test Invariant for `ResourceIndex::update_one()` Consistency

[tareknaser]

Description:

We should have tests for ResourceIndex::update_one() function (added in #85) to ensure that any sequence of update_one calls results in the same output as running update_all on the entire directory.

The process would involve starting with an empty directory, randomly generating an update (creation, modification, or deletion if applicable), applying update_one, and then building a new index from the current directory state. The results from both should be consistent. Property-based testing could also be explored for this case.

Relevant conversation: #85 (comment)