fstest/test_all: stop test servers on signal, panic, or exit

Until now test_all relied entirely on per-goroutine defer finish()
calls in fstest/runs to stop test servers. A Ctrl-C, kill, or panic
aborted those defers and left docker containers running, breaking the
next run.

Register testserver.CleanupAll with lib/atexit so SIGINT/SIGTERM
delivery runs the sweep automatically. Also defer atexit.Run for the
normal exit and unrecovered-panic paths, and call it explicitly
before os.Exit(1) since os.Exit does not fire defers. The fs.Fatalf
call sites above only fire before any server starts so they need no
explicit sweep.

fstest/test_all/test_all.go

@@ -24,6 +24,8 @@ import (
 	"github.com/rclone/rclone/fs"
 	"github.com/rclone/rclone/fs/config/configfile"
 	"github.com/rclone/rclone/fstest/runs"
+	"github.com/rclone/rclone/fstest/testserver"
+	"github.com/rclone/rclone/lib/atexit"
 	"github.com/rclone/rclone/lib/pacer"
 )
 
@@ -51,6 +53,13 @@ func init() {
 var Opt = &runs.RunOpt{}
 
 func main() {
+	// Make sure any test servers we start get stopped on exit or
+	// signal. Without this, a killed test_all run leaves docker
+	// containers behind (refcount never decrements) and breaks
+	// subsequent runs.
+	atexit.Register(testserver.CleanupAll)
+	defer atexit.Run()
+
 	flag.Parse()
 	conf, err := runs.NewConfig(Opt.ConfigFile)
 	if err != nil {
@@ -144,6 +153,7 @@ func main() {
 	report.EmailHTML(*Opt)
 	report.Upload(*Opt)
 	if !report.AllPassed() {
+		atexit.Run()
 		os.Exit(1)
 	}
 }