AGENTS.md@infrastructure/core/testing git:20260907.d6830feA

Immutable. This exact content is served forever at /api/v1/blob/3d8e76b5b65affe6.

# infrastructure/core/testing — agent contract

Test-execution machinery for the template: the per-project pytest runner,
profiles/markers, receipts, coverage probes, and the advisory test-impact
planner. Re-homed from the flat `infrastructure/core/` top level by
`CORE-TESTING-REHOME-1`.

## Invariants

1. `infrastructure/core/<module>.py` shims re-export this package's surface;
   old import paths must keep resolving (import parity is the re-home
   contract). New code imports `infrastructure.core.testing.<module>`.
2. Private names are package-internal. The shims re-export only the five
   externally-consumed privates (`_output_tree_digest`, `_contains_tests`,
   `_cache_identity_inputs`, `_resolve_roster_revision`,
   `_redact_output_tail`); everything else imports from the new path.
3. General core utilities (`determinism.py`, `script_discovery.py`,
   `runtime/`, `logging/`, …) stay at the core top level — membership here
   means "test-execution machinery", not "used by tests".

## Public surface

See `README.md` for the module table. Key entry points:
`run_per_project_pytest`, `build_union_pytest_command`, `resolve_test_profile`,
`write_public_matrix_receipt`, `run_project_test_matrix`, `output_tree_digest`,
`declared_output_relpaths`, `classify_changed_paths`, `check_cov_datafile_support`.

## Cross-refs

- `infrastructure/core/AGENTS.md` — the parent core contract.
- `tests/infra_tests/core/` — the suite exercising this package.
- Root `TO-DO.md` row `CORE-TESTING-REHOME-1` (closed by this re-home).