KeiSeiKit-1.0/skills/test-matrix/phase-3-scaffold.md

Phase 3 — Scaffold config + corpus + fixtures per cell

For each cell in MATRIX, generate the minimum-viable scaffold: one dependency declaration, one example test, one fixture / seed corpus, one local-run command. No over-scaffolding — just the "it runs" skeleton.

3a — Per-cell confirmation (AskUserQuestion, loop over cells)

For each cell, emit ONE AskUserQuestion:

{
  "questions": [
    {
      "question": "Scaffold plan for [<type> × <lang>] — proceed?",
      "header": "<type>/<lang>",
      "multiSelect": false,
      "options": [
        {"label": "Proceed with default scaffold",     "description": "Apply the default files listed below"},
        {"label": "Minimal only (dep + 1 test)",        "description": "Skip CI + corpus; just prove the toolchain runs"},
        {"label": "Edit one file",                      "description": "Reply with one free-text path — that file only gets custom content"},
        {"label": "Skip this cell",                     "description": "Drop from MATRIX; next cell"}
      ]
    }
  ]
}

Preview the default scaffold BEFORE asking, so the user sees what "proceed" means. Example for [fuzz × Rust]:

Default scaffold for [fuzz × Rust]:
  + fuzz/Cargo.toml           — cargo-fuzz manifest
  + fuzz/fuzz_targets/parse.rs — example fuzz_target!(|data: &[u8]| { ... })
  + fuzz/corpus/parse/seed_01  — one hand-picked valid input
  + fuzz/README.md             — local-run commands
Cite: _blocks/test-fuzz.md (corpus mgmt + triage + CI rules)

3b — Per-type default scaffolds

Cell	Files
fuzz × Rust	fuzz/Cargo.toml (cargo-fuzz), fuzz/fuzz_targets/<target>.rs, fuzz/corpus/<target>/seed_01
fuzz × Python	tests/fuzz/test_fuzz_<target>.py (atheris OR hypothesis in fuzz mode), tests/fuzz/corpus/
fuzz × JS/TS	test/fuzz/<target>.fuzz.ts (fast-check with numRuns: 10_000)
property × Rust	Cargo.toml adds proptest = "*", tests/property_<name>.rs, .proptest-regressions gitkeep
property × Python	tests/property/test_<name>.py with @given, .hypothesis/ gitignored except examples/
property × JS/TS	test/property/<name>.spec.ts with fc.assert(fc.property(...))
load × any	load/k6/baseline.js with SLO thresholds; load/README.md with baseline→profile→fix loop
e2e × any	e2e/playwright.config.ts, e2e/pages/login.page.ts, e2e/tests/login.spec.ts, e2e/README.md
mutation × Rust	.cargo-mutants.toml, first run command in tests/mutation/README.md
mutation × Python	mutmut config in setup.cfg / pyproject.toml, runbook in tests/mutation/README.md
mutation × JS/TS	stryker.conf.mjs with sane timeoutMS, mutate glob narrowed to critical paths

3c — Cite the block

Every scaffold file's header comment references the relevant _blocks/ file so the human reviewer can find the discipline rules:

// See _blocks/test-fuzz.md for corpus management + crash-triage rules.
// This file is the minimum skeleton; real targets expand from here.

Verify-criterion

• For every MATRIX cell, user clicked Proceed / Minimal / explicit Edit / Skip.
• At least one file is written per non-skipped cell.
• SCAFFOLDED is a list of {cell, files: [paths]} entries.
• No file overwrites an existing one without explicit confirmation (a PreWrite check: if path exists, emit a second AskUserQuestion "overwrite / skip / rename" before writing).