diff --git a/server_test.go b/server_test.go
index 6cd328a5..a12dc293 100644
--- a/server_test.go
+++ b/server_test.go
@@ -629,6 +629,10 @@ func checkInProgressQueriesAtShutdownServer(t *testing.T, srv *Server, addr stri
 	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() {})
 
 	HandleFunc("example.com.", func(w ResponseWriter, req *Msg) {
 		defer wg.Done()