port smoke to go

internal/smoketest/doc.go

@@ -0,0 +1,24 @@
+//go:build smoke
+
+// Package smoketest is the end-to-end smoke gate for banger's supported
+// two-service systemd model. It runs only when the build is tagged
+// `smoke`, which keeps it out of `go test ./...` on contributor
+// machines and CI.
+//
+// The suite touches global host state: it installs instrumented
+// bangerd.service + bangerd-root.service, drives real Firecracker/KVM
+// scenarios, copies covdata back out, then purges the smoke-owned
+// install on exit. It refuses to run if a non-smoke install is already
+// on the host (see the marker file under /etc/banger).
+//
+// The harness expects three env vars, normally set by `make smoke`:
+//
+//	BANGER_SMOKE_BIN_DIR    — instrumented banger / bangerd / vsock-agent
+//	BANGER_SMOKE_COVER_DIR  — coverage output directory (GOCOVERDIR)
+//	BANGER_SMOKE_XDG_DIR    — scratch root for fake homes, fake repos, etc.
+//
+// Coverage: the test binary itself is not instrumented, but every
+// banger / bangerd subprocess it spawns is, and writes covdata into
+// BANGER_SMOKE_COVER_DIR. Service-side covdata under /var/lib/banger
+// is copied out at teardown.
+package smoketest