Incompatible with nextest

[untitaker]

What happened?

with nextest, cargo insta approve only writes back changes for a single test. the repro steps have to be repeated 8-9 times until all dirty changes disappear from the git repo.

presumably because nextest runs each test in its own process and pending-snaps gets overwritten by each process.

Reproduction steps

1. check out https://github.com/untitaker/quickenv
2. change all snapshots in tests/acceptance.rs by a character or so
3. INSTA_FORCE_PASS=1 cargo nextest run
4. cargo insta approve

Insta Version

1.15.0

rustc Version

rustc 1.64.0-nightly

What did you expect?

one invocation of cargo insta approve should've captured all snapshot changes from all tests and approven them at once, undoing all uncommitted changes.

---

I wonder if .pending-snaps could:

1. become append-only (i.e. insta acquires a file lock and appends instead of overwriting file)
2. each entry contain hash of old/new snapshot content, so insta approve knows whether a "pending snap" is still relevant or can be skipped

[untitaker]

FWIW I don't think this is really worth fixing. I mostly found nextest useful for debugging flaky tests. cargo insta test works fine.