Contract tests (tests/meta/)

Fast, hermetic contract tests — plain pytest under the unit mark, no Docker, no GPU — that pin the modular-AirStack (RFC #379/#380) contracts: the airstack CLI's derived configuration, the module.yaml manifest and workspace overlay, stack folder anatomy, fleet files, the bridge → DDS-router generation, the doctor gates, the generated docs catalog, and the metrics reporting semantics. A "contract" here is a promise another part of the system (CI, docs deploys, an agent workflow, a module repo) relies on; these tests exist so a refactor cannot silently break the promise. They run in every airstack test -m unit invocation and in the unit-tests.yml PR gate.

Each test_*_contract.py file names the contract it pins in its module docstring — start there. Fixtures (e.g. the registry snapshot under fixtures/modules_index/) are committed copies of the external inputs the contracts were blessed against.

Two naming notes:

• tests/meta/ vs tests/harness/run_meta.py — unrelated despite the shared word. This directory holds contract tests ("meta" as in tests about the system's contracts rather than its flight behavior); harness/run_meta.py writes the run_meta.json run metadata file into each results directory. Neither imports the other.
• The lint outlier — test_launch_single_locus.py is not a fixture-based contract but a repo-wide lint: it walks the real launch tree and enforces the single-locus wiring rule (topic wiring lives only in stack entry files), with escape hatches listed in launch_lint_allowlist.txt.

See the main testing README for the one-line-per-file index.