feat(X402-47): fixture-consumption infrastructure + 3 hand-rolled D.x captures

[fardinvahdat]

Summary

X402-47 — closes the v0.3.2 audit-gate gap on D.2 / D.3 / D.5 verdict-synthesis paths. Ships fixture-consumption infrastructure + 3 hand-rolled captured-response fixtures covering one v0.3.2 D.x failure mode each. Hermetic, no live HTTP, no service-up dependencies.

What this PR adds

New directory: tests/fixtures/bazaar/captured-responses/

Three self-describing JSON fixtures, each capturing the three mock responses (well-known + challenge + discovery) needed to exercise one D.x verdict-synthesis path through runBazaarCheck end-to-end:

Fixture	Exercises	Models
d2-missing-propagation.json	metadata_propagation: missing → upstream_issue	@zev / TheRoosters / GM pattern
d3-processing-stuck.json	indexer_state: processing → upstream_stuck	Max's polyodds.bet (canonical #2207)
d5-body-discovery.json	BodyDiscoveryExtension shape → looks_correct (no false-positive)	AsaiShota test-echo-cdp + @0xdespot hyperD

Schema (self-describing)

{
  "$comment": "...",
  "scenario": "<slug>",                          // matches file basename
  "input": { "serviceUrl": "...", "chain": "base-sepolia" },
  "mocks": {
    "well-known": { "status": 200, "body": {...} },
    "challenge":  { "status": 402, "body": {...} },
    "discovery":  { "status": 200, "body": {...} }
  },
  "expected": {
    "verdict": "upstream_stuck",
    "exitCode": 3,
    "facets": { "indexing.indexer_state": "processing" }
  }
}

New integration test: tests/integration/bazaar-check-captured-responses.test.ts

Auto-discovers every .json in the fixture directory. For each fixture:

• Builds a mock fetcher dispatching by URL pattern (well-known / discovery / challenge fallback)
• Runs runBazaarCheck end-to-end
• Asserts the top-level verdict (kind + exitCode) match expected
• Asserts every per-check detail facet via dotted-path extraction (e.g., "indexing.indexer_state")
• Schema-checks the fixture itself (well-formed JSON, has all required keys)

Adding a new fixture is one JSON file — the harness picks it up automatically (no test code change required for new scenarios that fit the existing schema).

Scope cut vs original X402-47 AC

The original ticket called for consuming 6 named contributor fixtures:

• TomSmart cdp-mature (Sun drop)
• AsaiShota test-echo-cdp
• @evanatpizzarobot tensorfeed
• @0xdespot hyperd
• @hypeprinter007-stack anchor-x402 multi-rail
• TomSmart's existing 19-URL set (already in production-set/)

Reality: only TomSmart's first fixture is in the repo. The other 5 are pre-committed but not yet delivered (TomSmart's Sunday drop is ~24h out as of writing; the others are rolling).

This PR ships the infrastructure NOW with synthetic hand-rolled captures so the v0.3.2 audit gate has D.x coverage; real contributor fixtures wire in via the same harness as they arrive. The synthetic fixtures and the real ones coexist — no migration needed when contributor fixtures land.

Acceptance criteria (X402-47, satisfied at the infrastructure layer)

• Fixture loader handles a subdirectory (captured-responses/) — extending the loader for d4-targets/ + multi-rail/ is one-line work when those land
• At least one fixture per D.x facet captured (3 / 3 facets covered: D.2 + D.3 + D.5; D.4 covered by the pipeline test's --endpoint mode)
• Integration tests iterate over fixtures + assert sub-check decompositions
• AsaiShota's test-echo-cdp-shape produces looks_correct (NOT false-positive implementation_issue) under v0.3.2
• CHANGELOG ### Added entry documenting the new infrastructure + scope cut

Strict audit gate — abbreviated (user-in-loop mode)

• Stage 1 pre-work: branched off 6624e21 (PR feat(X402-46): D.3 indexer-state probe + upstream_stuck composite verdict #81 X402-46 + cap-bump merged); .gitignore WIP not staged
• Stage 2 implementation: new fixture directory + 3 JSON files + 1 new integration test file + CHANGELOG entry
• Stage 3 correctness: ✅ typecheck + lint + 511 tests pass (was 499; +12 captured-response tests) + build + check:publish-surface 102 files / 403 KB / 0 devDep imports (under both caps)
• Stage 4 edge cases: ≥7 — fixture file with malformed JSON (JSON.parse errors at load time, fails before tests run), fixture missing required keys (schema test fires per-fixture), URL-routing fallback (challenge URL = anything-not-well-known-or-discovery), facets block optional (test skips facet assertions when absent), unicode in service URLs, multiple resources in discovery body (uses first), $comment field as documented free-text (test ignores it)
• Stage 5 gap check: all 5 X402-47 AC items satisfied at the infrastructure layer; the 6-fixture contributor list is reframed honestly in the CHANGELOG as scope-cut + path-to-wire-in
• Stage 6 ship: this PR

What unblocks on merge

• X402-48 (release cut) — the only remaining v0.3.2 ticket. All D.x land + integration coverage land + JSON API stability land. Release-prep checklist can run.
• Real contributor fixtures (TomSmart Sun, AsaiShota test-echo-cdp, etc.) wire into this directory as they arrive — no new infrastructure needed

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Project	Deployment	Actions	Updated (UTC)
x402trace-dogfood	Ready	Preview, Comment	May 22, 2026 11:05pm