Revert "audio: No need goroutine for tests"

This reverts commit 7740656054.

audio/audio_test.go

@@ -71,14 +71,20 @@ func TestGC(t *testing.T) {
 	p = nil
 	runtime.GC()
 
-	for i := 0; i < 10; i++ {
+	ch := make(chan struct{})
-		got = PlayersNumForTesting()
+	go func() {
-		if want := 0; got == want {
+		defer close(ch)
-			return
+		for i := 0; i < 10; i++ {
+			got = PlayersNumForTesting()
+			if want := 0; got == want {
+				return
+			}
+			// 100[ms] should be enough all the bytes are consumed.
+			// TODO: This is a darty hack. Would it be possible to use virtual time?
+			time.Sleep(100 * time.Millisecond)
 		}
-		// 100[ms] should be enough all the bytes are consumed.
+		t.Errorf("time out")
-		// TODO: This is a darty hack. Would it be possible to use virtual time?
+	}()
-		time.Sleep(100 * time.Millisecond)
+
-	}
+	<-ch
-	t.Errorf("time out")
 }