Fixtures

Fixtures are the reproducibility contract of the ecosystem:

Fixture + Environment + Seed + Operation sequence = Reproducible result

Every fixture is versioned machine-readable JSON ("kind", "version": 1) whose shape is mirrored by JSON Schema files under schemas/. The loader rejects unknown kinds and unsupported versions.

Fixture kinds

• account — a synthetic identity account (identity + name + account_id).
• token — asset code, ID, issuer, decimals, confidential/registration/ transferable policy.
• environment — a named (seed) configuration a scenario runs under.
• scenario — an environment plus an ordered list of steps: create_account, create_named_account, create_native_asset, create_confidential_token, register, deposit, merge, transfer, withdraw, snapshot, restore, advance_ledger.

Failure scenarios declare "expected_error": "<code>" and are expected to end in failure with exactly that code; any other error — or success where failure was expected — makes the replay itself fail. This is also the shape of future regression fixtures: bug → fixture → test → permanent protection.

The canonical corpus

fixtures/
├── accounts/        alice, bob, carol, issuer, auditor
├── tokens/          confidential-token (CCT), native-test-asset (TEST)
├── balances/        confidential-balance state records
├── commitments/     commitment records
├── transactions/    transaction-record fixtures
├── successful/      deposit, transfer, withdrawal, full-lifecycle
└── failures/        insufficient-balance, unregistered-recipient,
                     double-registration

Environments are not separate files: every scenario fixture embeds the environment it runs under, so a scenario file alone is a complete repro.

A loader test replays the entire corpus on every run, keeping every checked-in fixture loadable and runnable.

Replaying

#![allow(unused)]
fn main() {
let loaded = load_fixture("fixtures/successful/full-lifecycle.json")?;
if let LoadedFixture::Scenario(scenario) = loaded {
    let outcome = run_scenario(&scenario)?; // ScenarioOutcome
}
}

ScenarioOutcome carries the resulting state fingerprint, step / transaction / event counts, and — for failure fixtures — the error code. Equal seeds produce equal outcomes (asserted); that is reproducibility in practice. When a contributor reports “transfer scenario fails”, the fixture file is the repro.