Not so much about testing, but one time I really needed to get to my backups I lost password to the repository (I’m using restic). Luckily a copy of it was stored in bitwarden, but until I remembered it, were perhaps one of the worst moments.
Needless to say, please test backups and store secrets in more then one place.
Syncthing plays nicely with obsidian if you ever have to synchronise the vault between multiple devices.