FS.GG.Game.Harness 0.12.0

FS.GG.Game.Harness

Deterministic, headless gameplay test harness on FS.GG.Game.Core. Drives a game's world through the standard Command input frontier, folds whole fixed steps, and fingerprints the world trace as a value — so a replay is a comparison, not a tolerance check.

Depends on nothing but FS.GG.Game.Core and the BCL — no render/input stack, no keymap type, no I/O (WI-6, Game#425). Everything below lives in the FS.GG.Game.Harness namespace.

The vocabulary

• Trace — the provenance-carrying comparison surface. A Trace<'f> is the world's evolution fingerprinted as a value, tagged with its Origin, so two runs are compared as data rather than re-simulated and eyeballed.
• Playable — the driven-game contract (Playable<'world,'key>) plus Bot<'view>, the in-process policy that turns a view of the world into commands. This is what a game implements to be driven by the harness.
• Driver — the drivers that produce a Run<'f>: scripted raw-key → keymap → Command input folded over whole fixed steps, and an in-process bot policy driving the same Command frontier.
• Journey — the stronger boot-to-outcome route. A ProductionJourney starts from a product's real boot function, drives timestamp-free host events through production mapping/update/tick/effect seams, and emits an opaque, bounded JourneyReceipt. Its Origin.ProductionJourney provenance is distinct from Playable's simulation/component evidence. fsgg-playtest obtains the receipt only by executing an IProductionJourneyProof and never accepts a caller-authored receipt file. emit-evidence serializes the validated receipt as a versioned journeyReceipt map and generates a JUnit report from that same in-memory execution. The shared execution id and receipt-binding digest mean a caller-supplied stale or fabricated TRX cannot stand in for the journey run.
• Workload — named expected-workload scripts and a product cost adapter. It keeps Release-only timing and bounded work observations separate from the deterministic Trace, and renders the generated scaffold's performance-evidence shape.
• Matrix — the multi-seed, bot-vs-bot match matrix. Seat, MatchSetup<'world,'view> and Match<'view> set up a seeded field of matches so a policy is exercised across many seeds, not one.
• Synthetic — the typed synthetic-state escape hatch: a labeled fallback that keeps its own evidence self-identifying, so a synthetic trace can never be mistaken for a real driven one.

Guarantees

Headlessly testable — zero Skia and zero Scene. It drives only through Game.Core's device-free Command vocabulary and whole fixed steps, so identical input replays byte-identically. The optional Workload.run clock feeds only WorkloadObservation; it never contaminates trace frames.

House style: .fsi is the sole public surface; net10.0; -preview channel. See FS-GG/FS.GG.Game and ADR-0022.