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deepseek-harness/docs/rfc/003-deterministic-and-stress-testing.md
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Tianyi Cui 4dafad4db6 Add RFCs for the remaining quality-proposal ideas
Eight proposals grouped by category, each with problem statement,
concrete plan, and risks: property-based testing over the
protocol-shaped core (chunk streams, event logs, schema DSL);
mutation testing as the counterweight to the 100%-coverage gate;
deterministic tests + a universal replay-invariant fixture + nightly
race stress; architectural conformance (dependency-cruiser rules and
the LlmAdapter conformance kit); runtime arg validation at the model
boundary with a structured error taxonomy and dev-mode invariants;
doc-sync enforcement (typechecked doc snippets, API reports);
supply-chain checks and nightly vendor-drift verification against the
manifest; and deep-readonly public surfaces (logged-vs-in-flight
mutability boundary). AGENTS.md points at docs/adr and docs/rfc.
2026-06-11 15:27:07 +08:00

1.7 KiB

RFC 003: Deterministic tests, the replay invariant fixture, and race stress

Status: proposed

Problem

Several loop tests synchronize with setTimeout(30) sleeps — flakiness debt that wastes agent cycles on retries and can mask ordering bugs. Separately, our core architectural promise (any session log replays to identical derived history) is asserted in two tests but is cheap to assert everywhere. And the inbox wakeup race was verified by hand exactly once; nothing re-verifies it continuously.

Proposal

Three measures:

  1. No wall-clock sleeps in tests. Replace setTimeout(N) waits with event-driven waits (the existing waitForIdle pattern, extended to waitForStatus, waitForEvent(n)) or vitest fake timers where time itself is under test. Enforce with a lint rule banning setTimeout in packages/*/tests outside an allowlisted helper module.
  2. Universal replay fixture. A shared test helper wraps the loop harness so that after every test, the agent's session log is replayed into a fresh Session and deriveMessages() equality is asserted automatically. The invariant then gets checked hundreds of times per CI run across every scenario the suite produces, not twice.
  3. Nightly race stress. A CI job running the agent-loop and inbox suites with vitest --repeat=200 (and --shuffle) to flush scheduling-dependent failures; any flake found is a bug to fix, never a retry.

Plan

Land 1 and 2 together (they touch the same helpers); add the nightly job after the suite is sleep-free so repeats are fast.

Risks

Fake timers interact subtly with Promise scheduling in the loop — prefer event-driven waits; reserve fake timers for timer-service behavior itself.