Engine.IO v3 frames over WebSocket prepend the packet-type byte (0x04
for Message) to BINARY frames, the binary analog of the leading digit
on text frames. The real client honors this and our session was
treating the entire binary frame as the Socket.IO attachment payload —
the msgpack decoder saw 0x04 as a positive fixint and failed
deserialization on every inbound msg event.
Symmetric fix: strip 0x04 from inbound binary frames in
BattleSession.RunAsync, prepend 0x04 to outbound binary frames in
EncodeAndSendAsync. RawSocketIoTestClient gets the same on both
directions so the integration test still exercises the same wire
shape as a real client.
Caught during v1 smoke walkthrough, after the WS upgrade started
succeeding (101 Switching Protocols).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Boots SVSimTestFactory (in-memory SQLite + reference-data CSV import),
mints a battle via IMatchingBridge, opens a raw Socket.IO v2 client
against the in-process TestServer, drives InitNetwork → Loaded → Swap,
and asserts the right scripted frames come back in order.
Verifies the full transport stack end-to-end: EIO3+SIO2 framing,
encryptForNode codec, MsgPayloadCodec roundtrip, InboundTracker
pubSeq dedup + ack echo, OutboundSequencer playSeq assignment, and
ScriptedLifecycle's Path-A frame builders.
Note: RawSocketIoTestClient.DisposeAsync skips the graceful CloseAsync
handshake — TestServer's in-process WebSocket implementation can hang
on it. Abrupt Dispose is fine: the server's ReceiveAsync throws
WebSocketException, BattleSession.RunAsync returns, and the handler
completes.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
