amethyst/nestsClient/tests/README.md

Cross-stack interop tests

Manually invoked. Not part of build.yml — see "Why not in CI" below.

Two suites that drive the production Amethyst Kotlin nests stack against external reference implementations of moq-lite-03:

Suite	Path	Runs	What it asserts
HangInteropTest	nestsClient/tests/hang-interop/	Rust hang-listen / hang-publish (kixelated reference) ↔ Amethyst Kotlin via a real moq-relay 0.10.x subprocess	Wire-byte capture, FFT peaks on decoded PCM, sample-count floors, mute / hot-swap / packet-loss / late-join / 60 s long broadcast / multi-listener fan-out.
BrowserInteropTest	nestsClient/tests/browser-interop/	Headless Chromium running @moq/lite + @moq/hang via Playwright ↔ Amethyst Kotlin (forward + reverse)	Same scenario family as hang-interop, plus WebCodecs AudioDecoder / AudioEncoder correctness, ALPN negotiation, browser-side reconnect.

Coverage matrix: nestsClient/plans/2026-05-06-cross-stack-interop-test-gap-matrix.md

When to run

Run both suites locally before merging any change that touches:

• quartz/.../nip53 (audio rooms event types, catalog wire format)
• nestsClient/src/.../moq/lite/ (moq-lite session, publisher/subscriber, codec)
• nestsClient/src/.../audio/ (capture, encoder/decoder, broadcaster, player)
• nestsClient/src/.../MoqLiteNestsSpeaker.kt / MoqLiteNestsListener.kt
• nestsClient/src/.../ReconnectingNests*.kt
• :quic (WebTransport, packet header protection, key updates, stream demux)
• The hang/browser sidecars themselves

Skip if the change is documentation, UI-only, build-script-only, or otherwise can't affect wire bytes / decoded audio.

Quick start

# Hang-tier (Rust ↔ Kotlin via real moq-relay subprocess)
./gradlew :nestsClient:jvmTest \
    --tests "com.vitorpamplona.nestsclient.interop.native.HangInteropTest" \
    -DnestsHangInterop=true

# Browser-tier (Chromium ↔ Kotlin) — also boots the moq-relay
./gradlew :nestsClient:jvmTest \
    --tests "com.vitorpamplona.nestsclient.interop.native.BrowserInteropTest" \
    -DnestsHangInterop=true \
    -DnestsBrowserInterop=true

# Both together
./gradlew :nestsClient:jvmTest \
    --tests "com.vitorpamplona.nestsclient.interop.native.HangInteropTest" \
    --tests "com.vitorpamplona.nestsclient.interop.native.BrowserInteropTest" \
    -DnestsHangInterop=true -DnestsBrowserInterop=true

The opt-in flags (-DnestsHangInterop=true / -DnestsBrowserInterop=true) also act as JUnit Assume gates — without them, the suites mark every scenario skipped rather than failing on missing prerequisites.

Prerequisites

Tool	Why	Install
Rust ≥ 1.95	moq-relay 0.10.25's transitive dep constant_time_eq 0.4.3 requires it	rustup install 1.95 && rustup default 1.95
cargo on PATH	Builds the hang-interop sidecars + cargo installs moq-relay, moq-token-cli	Comes with rustup
bun ≥ 1.3.x (browser only)	Bundles the Chromium harness + drives Playwright	curl -fsSL https://bun.sh/install | bash
Playwright Chromium (browser only)	Headless Chromium for @moq/lite + @moq/hang	Auto-installed by interopInstallPlaywrightChromium Gradle task

The Gradle build automates everything from there. First run installs and caches:

• moq-relay 0.10.25 + moq-token-cli 0.5.23 → ~/.cache/amethyst-nests-interop/hang-interop-cargo/bin/
• Sidecar release binaries → nestsClient/tests/hang-interop/target/release/
• bun's node_modules + dist/ → nestsClient/tests/browser-interop/
• Playwright Chromium → ~/.cache/ms-playwright/

Cold first run: ~10 min hang, ~13 min browser. Cached: ~3-4 min hang, ~5-7 min browser.

Configuration knobs

Flag	Default	Purpose
-DnestsHangInterop=true	unset (skip)	Enable HangInteropTest.
-DnestsBrowserInterop=true	unset (skip)	Enable BrowserInteropTest. Implies nestsHangInterop (the browser harness boots the same moq-relay subprocess).
-DnestsHangInteropTraceRelay=true	unset	Per-test moq-relay trace capture. Writes the relay subprocess's combined stdout/stderr (with RUST_LOG=info,moq_relay=trace,moq_lite=trace,moq_native=debug) to nestsClient/build/relay-logs/<methodName>-<seq>-<ts>.log. Use for debugging suite flakes.
-DnestsHangInteropDiagnostic=true	unset	Runs the Kotlin↔Kotlin variant gated separately (KotlinSpeakerKotlinListenerThroughNativeRelayTest) — useful to bisect wire-format bugs without involving Rust or Chromium.
BUN_BIN, NPX_BIN (env)	autodetected	Override the bun / npx binary path if your install lives outside the agent default (/root/.bun/bin/bun).

Known limitations

• chromium_listener_speaker_hot_swap_does_not_crash soft-passes its PCM assertion — Chromium's @moq/lite 0.2.x doesn't re-attach across Active::Ended → Active, so the browser captures only ~100 ms post-swap. T12 (group sequence carry across hot-swaps) is hard-asserted by the hang-tier counterpart.
• framesPerGroup is pinned to 5 in the test scenarios. Production defaults to 50. The two haven't been reconciled against a single multi-rig benchmark — see framespergroup-reconciliation.
• I7 cycle 2 truncation: moq-relay 0.10.x truncates the second cycle of a publisher reconnect at ~1.0 s out of ~2.5 s. Tests assert ≥ 2.5 s floor which the truncated cycle still clears; a future upstream fix may let us tighten further.
• I12 GOAWAY: not applicable to moq-lite-03; only the IETF moq-transport target (currently disabled) would exercise it.

Full open-issues list: 2026-05-06-cross-stack-interop-test-results.md § Pending follow-ups.

Debugging a flaking scenario

1. Re-run the failing scenario in isolation (no --tests filter races):

   ./gradlew :nestsClient:jvmTest \
       --tests "*HangInteropTest.late_join_listener_still_decodes_tail" \
       -DnestsHangInterop=true \
       -DnestsHangInteropTraceRelay=true \
       --rerun-tasks
   

2. Inspect nestsClient/build/relay-logs/<methodName>-*.log for subscribed started / encoding self=Subscribe / decoded result=SubscribeOk / subscribed cancelled events.
3. Cross-reference with the speaker-side Log.d("NestTx") lines captured in JUnit XML's <system-err> (nestsClient/build/test-results/jvmTest/TEST-*.xml) by timestamp.
4. The fastest diagnostic loop bypasses Browser/Chromium entirely — use the diagnostic test:

   ./gradlew :nestsClient:jvmTest \
       --tests "*KotlinSpeakerKotlinListenerThroughNativeRelayTest" \
       -DnestsHangInteropDiagnostic=true
   

Sample pre/post-merge trace pair for the previously-flaking late-join scenario lives at plans/artefacts/2026-05-07-routing-race-disproven/

• plans/artefacts/2026-05-07-routing-race-closed-by-merge/.

Why not in CI

Both suites are slow on a cold cache (~10–13 min each), and even on a warm cache the browser tier dominates the critical path at ~5-7 min. Running them on every PR doubles CI time for changes that don't touch audio / MoQ / QUIC.

History:

• 21947bc5 re-added both jobs after the T16 closure roadmap closed Priority 1 (:quic post-handshake bidi-drop fixed via origin/main merge) and Priority 2 (assertion hardening). 10/10 sweep × 22 tests = 220/220 hard-pass on the merged branch.
• A subsequent maintainer review judged the wallclock cost too high for the change-pattern (most PRs don't touch the relevant code) and removed the jobs.

The suites still run locally per the rules above. If a PR DOES touch audio / MoQ / QUIC code paths and the author hasn't run them, ask in review.

Files

• hang-interop/REV — pinned upstream versions (MOQ_RELAY_VERSION, MOQ_TOKEN_CLI_VERSION, HANG_VERSION, MOQ_LITE_VERSION, MOQ_NATIVE_VERSION). Bump deliberately.
• hang-interop/Cargo.toml + hang-{listen,publish}/, udp-loss-shim/ — Rust sidecar workspace.
• browser-interop/package.json + src/ + playwright.config.ts — bun + Playwright harness.
• nestsClient/src/jvmTest/kotlin/.../interop/native/:
  • NativeMoqRelayHarness.kt — boots the relay subprocess + captures per-test trace.
  • HangInteropTest.kt, HangInteropReverseTest.kt, HangInteropMultiListenerTest.kt, KotlinSpeakerKotlinListenerThroughNativeRelayTest.kt — hang-tier scenarios.
  • BrowserInteropTest.kt, PlaywrightDriver.kt — browser-tier.

See also

• 2026-05-06-cross-stack-interop-test.md — original spec / Definition of Done.
• 2026-05-07-t16-closure-roadmap.md — closure roadmap (Priorities 1, 2 closed; Priority 3 deferred).
• 2026-05-07-cross-stack-interop-ci-gating.md — the deferred CI-gating plan (kept around in case the wallclock cost calculus changes).