testing-codegen

# Testing and Code Generation Choose the narrowest test that exercises the changed behavior, then broaden only when shared infrastructure or integration risk justifies it. ## Test Selection | Change | Start with | | --- | --- | | Lint rule | `just test-lintrule <ruleName>` | | One crate | `cargo test -p <crate>` or the crate's focused test target | | Parser or formatter investigation | `just qt <package>` | | CLI migration | focused `biome_cli` migration tests | | Documentation code | `just test-doc` | Use `-- --show-output` or `--nocapture` only when the test's diagnostic output is needed. Quick tests are scratch space for inspecting CST, formatter IR, or one analyzer query. Persistent behavior belongs in the subsystem's normal fixture directory before finishing. ## Snapshot Workflow Run the focused test to produce snapshots, then review every changed section: ```shell cargo insta review ``` Use `cargo insta accept` or `cargo insta reject` only after inspecting the pending changes. A passing snapshot test proves output matches the checked-in snapshot, not that the snapshot describes correct behavior. ### Orphaned Snapshots Do not delete suspected orphan snapshots manually. Deletion is safe only after running the complete workspace snapshot suite without package, target, or test filters: ```shell cargo insta test --workspace --unreferenced delete ``` For a scoped run, use `--unreferenced warn` or `--unreferenced reject`; incomplete test selection cannot prove tha...