# Conformance tests — layout & requirement-tagging convention

Every test is a **Chainsaw `Test`** in its own directory:

```
tests/
  l1-rendering/        L1 — ServiceDefinition -> rendered resources match golden
  l2-behavioral/       L2 — real runtime behavior (probes against a cluster)
  l3-fault-injection/  L3 — break something; assert fail-closed / no-data-loss
  meta/                harness self-checks (R-TEST-*), cluster-independent
    <test-name>/chainsaw-test.yaml
```

The layer a test belongs to is its subtree **and** its `.../layer` annotation; the
coverage generator cross-checks the two.

## Requirement-tagging convention (authoritative)

A test declares the requirement(s) it verifies **three** ways; the label is the source
of truth, the annotations must agree with it (the coverage generator fails on drift):

```yaml
metadata:
  name: default-deny
  labels:
    # ONE label per verified R-* ID. Machine-selectable + coverage source of truth.
    conformance.home.k3s/R-NET-01: "true"
  annotations:
    # Human-readable canonical list — MUST equal the label set.
    conformance.home.k3s/requirements: "R-NET-01"
    # Declared layer (L1|L2|L3|META) — must match the subtree.
    conformance.home.k3s/layer: "L2"
    # true => R-TEST-05 requires this to be (or have) an L3 fault-injection test.
    conformance.home.k3s/safety-critical: "false"
    # Given/When/Then intent, for the coverage report and reviewers.
    conformance.home.k3s/intent: "Given ... When ... Then ..."
```

Why a label **per requirement** (not a comma list): Kubernetes label *values* can't hold
a comma-separated list, and `chainsaw test --selector` selects on label **keys/values**.
One `conformance.home.k3s/<R-ID>=true` label per requirement makes both subset-selection
and coverage extraction exact and robust.

### How this drives the tooling
- **Subset runs (merge gate):** `run.sh --requirements R-NET-01,R-NET-06` resolves the
  R-IDs to the set of test dirs carrying those labels (union, deduped) and runs each once.
- **Coverage (`lib/coverage.py`):** reads these labels from every `chainsaw-test.yaml`,
  maps each registry requirement -> its verifying test(s), and flags gaps + any
  label/annotation mismatch + tags not in the registry.
- **JUnit:** results (real or skipped-scaffold) carry the R-IDs in `classname` +
  properties, so the JUnit itself stays traceable (R-TEST-04).

## Authoring rules (R-TEST-01/02/06)
- **Behavior, not existence.** Assert what the system *does* (a probe cannot connect),
  never that an object merely exists (a policy can exist and not enforce).
- **Given/When/Then** structure with `given-*/when-*/then-*` step names.
- **Hermetic & self-cleaning.** Rely on Chainsaw's per-test namespace + auto-teardown;
  put any out-of-namespace fixture cleanup in a `finally` block. A leaked fixture is a
  failure.
- **Bounded, deterministic waits.** Use assert/error polling within the config timeouts;
  never `sleep`-and-hope.
- **Safety-critical => fault-injection.** For a safety-critical requirement, actually
  break the thing and assert fail-closed / no-data-loss, with `finally` restoring state.
- **Never weaken a test to go green (R-TEST-06).** If the spec can't be met, escalate to
  the PM — do not relax the assertion or the requirement.

Scaffolds in this tree carry `TODO(T-x.y)` markers where a fixture/assertion lands as a
later roadmap phase delivers the capability under test.