The black-box monitor tests showed socketv1_controller.go and
socketv2_controller.go were near-identical: same constants (identical
values), upgrader, read/write pumps, Close, and handler bodies, differing
only in the event payload shape and v1 dropping deletions.
Extract the shared machinery into socket_controller.go:
- msgListener[T] generic listener with toStored/toDeleted payload
transforms; a nil toDeleted preserves the socketv1 behavior of ignoring
deletions
- socketReadPump / socketWritePump free functions (WriteJSON is
payload-type agnostic)
- serveMonitor shared handler body (upgrade, gauge tracking, listener
registration, pump wiring)
The version files shrink to their listener constructors and the four
exported handlers, whose signatures are unchanged. v1 payloads are now
shaped at enqueue time rather than write time; the JSON on the wire is
identical, pinned by the commit-1 tests, which pass unmodified.
Adds direct unit tests for the extracted listener logic: watches()
filtering, Receive/Delete filtering + payload shaping, nil-toDeleted
deletion dropping, and sequential Close idempotency.
Cover the REST WebSocket monitor endpoints (v1 + v2), previously at 0%
for all 18 functions in socketv1_controller.go and socketv2_controller.go;
pkg/rest coverage goes from 20.9% to 73.2%.
The harness dials a real gorilla/websocket client into an httptest server
wired to a running msghub.Hub, and relies on the hub's history replay for
deterministic ordering: dispatching before dialing seeds the replay, and
events are relayed in dispatch order, so receiving event N next proves
filtered events were skipped rather than delayed.
Covered for both API versions:
- monitor-all and per-mailbox endpoints, including history replay and live
delivery, and mailbox filtering of both message-stored and (v2)
message-deleted events
- address-form mailbox names via Manager.MailboxForAddress (user%40example.com)
- invalid mailbox names rejected with 500 before the upgrade, and plain GET
requests failing the handshake with 400
- client data messages discarded by the read pump
- clean client shutdown: listener deregistration, empty close frame from
the writer racing the read pump's close-code echo, and the
WebSocketConnectsCurrent expvar gauge increment/decrement
Tests only; no production changes. Notes for follow-up commits:
- v1 monitors ignore deletions while v2 reports them (pinned as current
behavior in TestMonitorMailboxMessagesV1)
- httptest.Server.Close does not wait for hijacked connections, so
dialMonitor's cleanup awaits the handler goroutine via the connections
gauge before the hub is stopped; the read/write pumps calling
msgListener.Close concurrently can still double-close its channel
(check-then-act race in Close's select) and deserves a fix
- deadline-set error paths, the 54s ping/pong cycle, and write-failure
paths remain uncovered, consistent with the POP3 send-error paths
James Hillyerd