Ensure that `update_all` and `update_one` are consistent

[kirillt]

• [ ] Unit tests covering update_one
• [ ] Unit tests covering update_all

Then, we want to verify that:

• update_all can be replaced by multiple update_one

• [ ] Unit tests for simple cases with both update_all and update_one

• [ ] Randomized test scenario checking different combinations

[mberry]

The issue I see arising with update_one is that it takes a new path and old id, but also uses the path as a key with self.path2id[path] before updating the index. Think some of the functions need to be run in a different order, like the collision check at the end before returning