cintegration: mock daemon lifts coverage past FFI-bound ceiling#3
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The previous iteration drove libpilot's //export surface from C, but
every endpoint requiring a connected handle (PilotInfo, PilotHealth,
PilotDial, PilotListen, the entire Network*/Managed*/Policy* surface,
trust handshake variants, conn read/write) was blocked at the
loadHandle()/driverFromHandle() gate. Coverage capped at 20.8%.
Adds a standalone mock daemon binary (cintegration/mockdaemon/main.go)
that speaks the bare IPC wire protocol — length-prefixed frames with
a single command byte, no JSON RPC, no handshake. It services every
request type with canned replies sufficient for libpilot to round-trip
a real handle:
- 0x01 Bind -> 0x02 BindOK [port(2)]
- 0x03 Dial -> 0x04 DialOK [connID(4)]
- 0x06 Send -> echoed back via 0x07 Recv push
- 0x08 Close -> server-pushed 0x09 CloseOK so reads see EOF
- 0x0D Info -> 0x0E InfoOK [JSON]
- 0x0F Handshake -> 0x10 HandshakeOK [JSON] (sub-cmds dispatched)
- 0x11 Resolve -> 0x12 ResolveOK [JSON]
- 0x13 SetHostname -> 0x14 SetHostnameOK [JSON]
- 0x15 SetVisibility .. 0x29 Broadcast
-> matching XxxOK code with JSON or empty payload
The C harness forks the mock binary into a temp Unix socket, polls
until the socket appears (capped at 2s), then runs 41 new tests
covering every handle-bound endpoint plus a write/echo/read round
trip over a dialled Conn. Mock is SIGTERMed at end.
Result: 70 tests (29 pre-existing + 41 mock-driven), all passing on
darwin/arm64. Per-statement coverage climbs from 20.8% to 66.3%.
Per-function coverage of bindings.go now shows nearly every PilotXxx
between 71% and 100%; only PilotRecvFrom (needs spontaneous CmdRecvFrom
push), PilotListenerAccept (would block indefinitely without a peer
dialling in), and PilotDialTimeout's success branch (mock doesn't
inject delay) remain partially covered. main() is cgo-only and not
test-reachable in any harness.
Protocol details I reverse-engineered vs. canned:
- Wire frame format from internal/ipcutil/ipcutil.go (length-prefixed)
- Cmd constants from pkg/driver/ipc.go (canonical numbering)
- Reply payload shapes from pkg/daemon/ipc.go handlers (handleBind,
handleDial, handleInfo, sendError)
- Driver demux behaviour from pkg/driver/ipc.go readLoop: known
XxxOK cmds route to a single in-flight pending channel; CmdRecv /
CmdCloseOK / CmdAccept are server-pushed and routed by ID
- No IPC-layer Ed25519 handshake; identity is daemon-to-daemon only.
A fresh Unix-socket connection sends frames immediately.
What is NOT modified: bindings.go, embedded.go, coverflush.go.
Mock daemon lives entirely under cintegration/mockdaemon/ with its
own go.mod so it never affects the libpilot module graph.
Codecov Report✅ All modified and coverable lines are covered by tests. 📢 Thoughts on this report? Let us know! |
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Summary
cintegration/mockdaemon/) speaks the bare IPC wire protocol so the C harness can drive everyPilot*endpoint that requires a connected handle.SIGTERMs on exit. 70 tests total (29 pre-existing + 41 new), all passing on darwin/arm64.bindings.gonow sits between 71-100% for nearly everyPilot*export.Protocol notes
The IPC layer is simpler than expected: length-prefixed frames (
[uint32-be-len][cmd-byte][payload]), no hello/handshake, no Ed25519 negotiation. Identity is daemon-to-daemon, not on the local socket. The mock supports:Reverse-engineered from
web4/internal/ipcutil,web4/pkg/driver/ipc.go,web4/pkg/daemon/ipc.go. Reply payload shapes (e.g. CmdBindOK =[port(2)], CmdDialOK =[connID(4)]) match the daemon handlers inpkg/daemon/ipc.go.What is NOT touched
bindings.go,embedded.go,coverflush.go— production code untouched per task constraints.cintegration/mockdaemon/with its owngo.mod, no effect on the libpilot module graph.Endpoints still uncovered
PilotRecvFrom— needs spontaneousCmdRecvFromserver push. Can be added by spawning a goroutine on the mock side that pushes a canned datagram on a timer.PilotListenerAccept— would block indefinitely without a peer dialling into the listener; out of mock scope (would need a second client driving inbound dials).PilotDialTimeoutsuccess branch — mock replies instantly; the timeout path is exercised by the existingdial_timeout_hugeinvalid-handle test.main— cgo entry, never reachable in any harness.Test plan
cd cintegration && make clean && make coveron darwin/arm64 -> 70/70 pass, total 66.3%go test ./...on libpilot module still green