test(engine): gate the catalog against the card that was printed

[ninthworld]

Closes #822. Part of #819. Stacked on #829 — review that first; this PR's diff against main will collapse to its own once #829 merges.

build.rs validates a definition's shape. It cannot know a number is wrong, and the behavioural tests assert against whatever the definition says — so they cement the bug rather than catch it. Fifteen cards shipped that way (#820); twelve differed in a field a machine can check.

What lands

• crates/sage-engine/tests/fixtures/printed_characteristics.json — one record per catalog card: name, mana cost, supertypes, types, subtypes, power, toughness, loyalty, colours. 72 KB.
• crates/sage-engine/tests/printed_characteristics.rs — five tests: both directions of the catalog↔fixture correspondence, the characteristics themselves, second faces, and the licensing constraint.
• scripts/printed-characteristics.py — regenerates the fixture from a third-party set file.

The one rule that keeps it honest

The script reads the set file and the catalog's identities (functional_id, name). It never reads a definition's characteristics. A fixture regenerated from the thing it checks is a gate that passes forever and proves nothing — that's the failure mode this is designed against, and it's stated in the script, in the test's module doc, in docs/card-schema.md, and in the engine AGENTS.md.

Falsification

Reverting two of #829's fixes and running the gate:

the catalog disagrees with the card that was printed:
  marauder_s_axe: mana_cost is "{3}", printed "{2}"
  regal_bloodlord: mana_cost is "{3}{B}{B}", printed "{3}{W}{B}"
  regal_bloodlord: subtypes is ["Vampire", "Noble"], printed ["Vampire", "Soldier"]
  regal_bloodlord: colors is [Black], printed [White, Black]

Card and field, named.

Licensing

AGENTS.md forbids shipping rules text, flavour text, art, symbols, or branding. The fixture carries the same functional data ADR 0009 already sources for the catalog itself and nothing else. deny_unknown_fields refuses anything else structurally; a test also states the allowed set outright, because the reason lives in AGENTS.md rather than in serde.

What it does not catch, stated plainly

Rules text is out of scope — it cannot be checked without storing it, and storing it is the one thing the rule forbids. Of #820's fifteen wrong cards this catches twelve. A missing {R} in a cost list, a gain_life the card does not print, a token created tapped: those stay a human-review problem, held by the behavioural tests instead. The module doc says so rather than implying broader coverage.

* is not a number

Enigma Drake's printed power is *. The fixture keeps power as a string, and a * is satisfied by a defined_power ability rather than by a value — so a base of 0 with nothing to define it fails, which is a 0/4 wearing a *'s clothes.

Costs 0.02s in make check. make verify green.

🤖 Generated with Claude Code