Conformance & fixtures

Wire compatibility is proven, not asserted. Two instruments hold Undertow to the reference behavior:

1. Golden wire fixtures — raw frame transcripts captured from the Gleam Floodgate reference server by tools/Undertow.WireDiff (record mode), stored in tests/fixtures/wire/. These are the byte-level contract.
2. Conformance suites — Floodgate’s Routerlicious and Phoenix/cross-mode suites, run against one live Undertow process.

Recorded results

Recorded 2026-08-07 against Floodgate at 2687b5f. Counts move with the repository; the fixtures are the authority.

Suite	Result	Remarks
Routerlicious conformance	38 pass	3 skipped, 1 todo — the reference suite’s own baseline
Phoenix + cross-mode conformance	7 pass	both protocols against one process
Drop-in parity vs. Levee suite	53 / 54	the one non-pass is an intentional 401 (ADR-009)
Readiness checks	8 / 8
levee-example integration	15 pass	levee-client against Undertow
Unit + integration tests	187 pass	dotnet test Undertow.slnx
todo-list multi-user e2e	9 / 9	live browser flow through the real container loader

Running the gates

just test              # unit + integration tests
just test-dual-mode    # Floodgate's Routerlicious and Phoenix/cross-mode suites

just test-dual-mode builds and starts a local Undertow process, waits for /health, then runs the conformance suites from a Floodgate checkout (location configurable via FLOODGATE_REPO, default ../floodgate).

The fixture transcripts

Line prefixes: > sent to server · < received · # annotation · >A / <B / <P label the socket in multi-socket scenarios.

File	Scenario
rest-basics.txt	/health (GET+HEAD), token mint, create document, session, deltas, missing auth
socketio-write-connect-op.txt	Engine.IO open, 40 connect, write-mode connect_document (IConnected), submitOp → sequenced op
socketio-read-nack.txt	read-mode connect, submitOp → 403 nack
socketio-auth-failures.txt	expired token, bad signature → connect_document_error
socketio-unicode.txt	non-ASCII + <&> in user.name — raw UTF-8 on the wire, no \uXXXX escapes
signals-broadcast-targeted-leave.txt	2 Socket.IO + 1 Phoenix client; legacy broadcast signal; v2 targeted signal; disconnect → sequenced leave op
phoenix-write-connect-op.txt	two-phase join, connect_document push, submitOp → op push, heartbeat, phx_leave, phx_close
phoenix-bad-vsn.txt	vsn=1.0.0 rejected before upgrade

SOURCE.txt alongside the fixtures records the exact reference commit and capture time. The fixtures were re-captured 2026-08-07 after the assert-0x4b2 fix landed in the Gleam reference (see Divergence notes).