---
id: suite-scaffold
name: Conformance suite — home, convention, and invariant backlog
status: completed
depends_on: [scaffold-crate-features]
scope: narrow
risk: low
impact: project
level: implementation
tags: [wave-1, suite]
---

## Description

Establish `tests/conformance/` — the in-crate conformance harness home
(decided point: engines are features of one crate, so the suite lives
in-crate, factory-parameterized over engine constructors; the
alkstore ADR-017/022 pattern adapted) — with the convention that waves
2–6 grow columns against:

- **The convention document** (a `tests/conformance/README.md` or
  module doc): row naming, the ADR-stamp format (every row cites the
  ADR § / spec § that pins it — the alkstore version-stamping
  convention), the one-normative-owner-per-property rule, and the
  factory contract: each factory opens a **fresh, isolated** store
  instance (no shared state between rows) with **idempotent
  teardown**; engine factories for SQL engines skip cleanly when no
  server is reachable (the alkstore SKIP posture) while acceptance
  requires green against the server.
- **The invariant backlog**: store-api.md's seven invariants
  registered as the rows-to-grow table (round-trips per engine/tier/
  put-path; dedup; stage hygiene; sweep safety incl. the engine-gated
  fleet form; list-correctness-through-sweep-outcomes; `stat`-without-
  content; engine-conformance uniformity) — each row's first column
  lands with the mem engine in wave 2 (mem is the contract-reference
  engine; every other engine's rows mirror its column).
- **The harness skeleton**: the factory trait shape and the row
  registration structure, compile-able as a stub (the `Store` facade
  type arrives in wave 2 — the skeleton pins the shape, wave 2's
  first column binds it; if binding reveals a shape correction, that
  is wave 2's to make and record).

This task is deliberately convention-first: the harness shape is
easier to grow row by row as engines land than to retrofit onto five
finished engines (the alkstore wave-1 rationale, which applies
identically here).

## Acceptance Criteria

- [ ] `tests/conformance/` exists with the convention doc (row naming,
      ADR-stamp format, one-owner rule, factory isolation + teardown
      contract, SKIP posture)
- [ ] The invariant backlog table registered, traceable to
      store-api.md's seven invariants, with the mem-first column plan
      noted
- [ ] The harness skeleton compiles (`cargo test` green — a stub with
      no rows yet is acceptable and expected)
- [ ] No engine-specific code; the task adds no dependencies

## References

- docs/architecture/store-api.md (§Invariants — the test gate)
- docs/architecture/backends-and-dispatch.md (§Per-engine conformance; POC #7 gate as the norm)
- /workspace/@alkdev/alkstore/docs/plans/implementation.md (wave 1 + wave 5 sections — the convention's source pattern)
- docs/plans/implementation.md (Decided points — suite home)

## Notes

- The convention doc landed as `tests/conformance/README.md` (normative
  home) with the in-code anchors: `stamp.rs` (the `Contract stamp:`
  marker, alkstore ADR-017 §4.2 adapted), `factory.rs` (the
  `StoreFactory` shape + contract), `backlog.rs` (the backlog as an
  in-code registry with a traceability gate).
- The skeleton's wave-2 binding point: `StoreFactory::Store` is an
  associated type placeholder for the `Store` facade type (which
  arrives in wave 2 — no public type exists to bind today). Wave 2's
  mem column binds it; a binding-revealed shape correction is wave
  2's to make and record in README + factory.rs, per the task text.
- SKIP posture is pinned as convention text (README §SKIP posture +
  factory.rs docs) rather than typed machinery: the mechanism lands
  with the first column that needs it (postgres, wave 4). Mem/sqlite/
  local never skip.
- The backlog table cites per-entry: restated invariant, planned row
  family, pinning texts (spec §/ADR §), first column/wave. INV-4's
  fleet form is recorded as its own engine-gated family (wave 6).
- Harness self-checks (4 tests): backlog traceability (order mirrors
  store-api.md §Invariants 1–7, every field populated), stamp marker
  identity, and a probe factory proving the trait is implementable
  with async methods (the alkstore exemplar-against-mock posture,
  sized to the no-rows state). No engine-specific code; no
  dependencies added.

## Summary

`tests/conformance/` established: README.md (row naming, stamp
format, one-owner rule, factory isolation + idempotent-teardown
contract, SKIP posture, the seven-invariant backlog table traceable
to store-api.md, mem-first column plan), plus the compile-able
skeleton (factory trait, stamp module, backlog registry) with zero
rows as expected. Verified: `cargo test` (33 total across lib + 3
targets), `cargo clippy --all-targets -- -D warnings`, `cargo fmt
--check` all green.