cratefield-testing

The conformance kit every Factory Zero module runs against — public and private modules alike. Fake ports, an in-memory SQLite Database, and request helpers over the axum router with no network.

A 15-line module test

use cratefield_testing::{conformance, request, TestHarness};

#[test]
fn my_module_conforms() {
    conformance(Box::new(my_module::MyModule::new()));
}

#[pollster::test]
async fn join_accepts_an_email() {
    let kit = TestHarness::new(vec![Box::new(my_module::MyModule::new())]);
    let res = request(&kit.router, http::Method::POST, "/v1/my-module/join",
        Some(r#"{"email":"nick@example.com"}"#)).await;
    assert_eq!(res.status, http::StatusCode::ACCEPTED);
    assert_eq!(kit.mailer.sent().len(), 1); // the confirmation mail
}

What you get

• TestHarness::new(vec![Box<dyn Module>]) — builds the harness with every port faked, applies each module's sqlite migrations to a fresh in-memory database, assembles the router. Exposes { router, mailer, captcha, rate_limiter, db, clock, kv, http, defer, signer, events, modules, dialect }.
• Parity (issue #20): TestHarness::with_database(modules, Dialect::Sqlite | Dialect::Postgres { url }) runs the same harness on a throwaway Postgres 16 database (per-harness, dropped on drop; needs the crate's postgres feature and a server at FZ_TEST_POSTGRES_URL). TestHarness::all_dialects(make_modules) / all_dialects_with_ports(make_modules, patch) build one kit per dialect available in the environment so a module suite loops over them — one test definition, every engine. The module factory runs once per dialect: modules may carry per-build state, so kits never share instances.
• Fakes: FakeMailer (records Messages; SendOk/NotConfigured/Fail modes, switchable mid-test), FakeCaptcha (allow-all or token list), FakeRateLimiter (scripted Decisions + call count), FixedClock, MemoryKeyValue, FakeHttpClient (scripted responses + captured requests), EmptyDatabase (services SELECT 1 only), FakeDefer (collects deferred futures; drain().await runs them), and a Signer with the fixed dummy TEST_HARNESS_SECRET.
• request(&router, method, path, json?) -> TestResponse { status, headers, json() } — tower::ServiceExt::oneshot, no network.
• conformance(module) — the shared suite, run once per available dialect: mounts + health listing, request under the prefix, migrations apply twice on fresh databases, view_for hides undeclared ports, the two-concurrent-requests request-id test (ADR 0007), and — for modules with a well_known router — that it serves at the root /.well-known and never under /v1 (#46).
• assert_wasm_safe_deps(env!("CARGO_PKG_NAME")) — cargo tree check: no worker/wasm-bindgen/tokio/reqwest in the module's normal dependency tree.

The in-memory Database is cratefield-adapter-sqlite; assertions on kit.db see exactly what the module wrote. On the Postgres leg kit.db is a pool on the kit's own tokio runtime marshalled per call, so pollster-driven tests, spawned threads and deferred handlers all reach it.