Use an atomic int32 in checkInProgressQueriesAtShutdownServer (#779)

server_test.go

@@ -9,6 +9,7 @@ import (
 	"runtime"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"testing"
 	"time"
 
@@ -625,17 +626,15 @@ func init() {
 func checkInProgressQueriesAtShutdownServer(t *testing.T, srv *Server, addr string, client *Client) {
 	const requests = 100
 
-	var wg sync.WaitGroup
-	wg.Add(requests)
-
 	var errOnce sync.Once
 	// t.Fail will panic if it's called after the test function has
 	// finished. Burning the sync.Once with a defer will prevent the
 	// handler from calling t.Errorf after we've returned.
 	defer errOnce.Do(func() {})
 
+	toHandle := int32(requests)
 	HandleFunc("example.com.", func(w ResponseWriter, req *Msg) {
-		defer wg.Done()
+		defer atomic.AddInt32(&toHandle, -1)
 
 		// Wait until ShutdownContext is called before replying.
 		testShutdownNotify.L.Lock()
@@ -708,23 +707,15 @@ func checkInProgressQueriesAtShutdownServer(t *testing.T, srv *Server, addr stri
 		})
 	}
 
-	done := make(chan struct{})
-	go func() {
-		wg.Wait()
-		close(done)
-	}()
-
 	ctx, cancel := context.WithTimeout(context.Background(), client.Timeout)
 	defer cancel()
 
 	if err := srv.ShutdownContext(ctx); err != nil {
-		t.Errorf("could not shutdown test server, %v", err)
+		t.Errorf("could not shutdown test server: %v", err)
 	}
 
-	select {
-	case <-done:
-	default:
-		t.Error("ShutdownContext returned before replies")
+	if left := atomic.LoadInt32(&toHandle); left != 0 {
+		t.Errorf("ShutdownContext returned before %d replies", left)
 	}
 
 	if eg.Wait() != nil {