Choruz CI Test Reliability

Reliable Choruz CI tests

When loaded from a personal skills directory, resolve repository links from this skill's canonical .agents/skills/choruz-ci-test-reliability/ location in the active Choruz checkout, not from the installed copy.

Build tests that remain correct under the repository's real CI topology, not only when run alone on a quiet workstation. This skill owns isolation and reliability decisions; docs/testing/pr-test-policy.md owns which tests a change must add, and choruz-pre-push-checks owns which commands to run before a push.

Model the execution topology

Assume these layers overlap unless the active configuration proves otherwise:

1. Playwright: apps/web/playwright.config.ts runs with fullyParallel and two workers on CI (CHORUZ_E2E_WORKERS), sharded across jobs (--shard=n/m). Every worker talks to the same API, the same PostgreSQL and the same pipeline started by infra/host/web_e2e.sh; only the browser context is private. retries: 1 on CI means a test that passes on retry is reported as flaky, not as passing.
2. vitest: apps/web unit tests run in worker processes; module state, process.env, timers and localStorage mocks are per file, not per test.
3. cargo: integration tests under crates/ and services/ share the database created by infra/host/setup_test_database.sh; tests in one binary run on parallel threads.
4. Jobs: the e2e shards, the Rust jobs and the smoke jobs run at the same time on separate runners; they do not share a host, but they do share GitHub's artifact and cache services.

Process isolation does not isolate database rows, ports, predictable filesystem paths or inherited child processes. For every acquired resource, identify its owner, its allocation mechanism, its readiness signal, its cleanup, and its quiescent completion signal.

Own your data

The single most common Choruz flake is a test that reads global state another worker is writing.

• Create what you assert on. Seed a group with createGroup(page, token, principal.id, uniqueName("…")), an agent with provisionAgent, a message with sendMessage; then assert on those ids and names, never on "at least one exists" or "the first item".
• Never compare absolute counts taken at two moments (countAfter === countBefore): another worker can add a row in between. Assert the filtered result is empty and the restored list contains the seeded item, or use toBeGreaterThanOrEqual with the seeded item present.
• Never assume an empty workspace, an empty conversation list, or that a default agent exists.
• Use data-conversation-id and other stable attributes instead of visible text that other workers can also produce.
• In cargo tests, give rows unique names or ids per test and scope queries to them; never truncate a shared table.

Allocate resources atomically

• Ports come from the environment (CHORUZ_API_PORT, CHORUZ_WEB_PORT, CHORUZ_PIPELINE_METRICS_PORT, CHORUZ_PG_PORT) that web_e2e.sh already isolates per run; a test never binds a fixed port of its own. A Rust test that needs a listener binds port 0 and reads the assigned address.
• Temporary files use a private per-test directory (tempfile::tempdir(), mkdtemp), never a predictable path.
• Route mocks (page.route) match the exact request the test owns, not a prefix another flow also hits.

Synchronize on state

A fixed waitForTimeout is not evidence that setup completed or that cleanup settled.

• Wait for the observable condition: expect(locator).toHaveCount(n), expect.poll(...), a readiness endpoint, an owned promise.
• Message delivery in the web app arrives through the sync feed; wait for the bubble with the seeded content, not for a duration.
• Use a timeout only to bound a wait, never as the condition that makes the assertion correct.
• When time itself is the subject, inject or fake the clock and always restore real timers.