small optimizations

Overlord-Client/cmd/agent/webrtcpub/state_test.go

@@ -0,0 +1,69 @@
+package webrtcpub
+
+import (
+	"sync"
+	"testing"
+	"time"
+)
+
+type blockingVideoWriter struct {
+	started chan struct{}
+	release chan struct{}
+	mu      sync.Mutex
+	frames  [][]byte
+}
+
+func (w *blockingVideoWriter) WriteH264(frame []byte, _ time.Duration) error {
+	w.mu.Lock()
+	w.frames = append(w.frames, append([]byte(nil), frame...))
+	count := len(w.frames)
+	w.mu.Unlock()
+	if count == 1 {
+		close(w.started)
+		<-w.release
+	}
+	return nil
+}
+
+func TestWriteH264DoesNotBlockAndKeepsLatestPendingFrame(t *testing.T) {
+	kind := Kind("queue-test")
+	id := "slow-writer"
+	writer := &blockingVideoWriter{
+		started: make(chan struct{}),
+		release: make(chan struct{}),
+	}
+	registerVideoWriter(kind, id, writer)
+	defer unregisterWriter(kind, id)
+
+	if err := WriteH264(kind, []byte{1}, time.Millisecond); err != nil {
+		t.Fatal(err)
+	}
+	select {
+	case <-writer.started:
+	case <-time.After(time.Second):
+		t.Fatal("writer did not receive first frame")
+	}
+
+	started := time.Now()
+	_ = WriteH264(kind, []byte{2}, time.Millisecond)
+	_ = WriteH264(kind, []byte{3}, time.Millisecond)
+	if elapsed := time.Since(started); elapsed > 100*time.Millisecond {
+		t.Fatalf("capture path blocked for %s", elapsed)
+	}
+	close(writer.release)
+
+	deadline := time.Now().Add(time.Second)
+	for time.Now().Before(deadline) {
+		writer.mu.Lock()
+		frames := append([][]byte(nil), writer.frames...)
+		writer.mu.Unlock()
+		if len(frames) >= 2 {
+			if frames[0][0] != 1 || frames[1][0] != 3 {
+				t.Fatalf("expected first and latest frames, got %v", frames)
+			}
+			return
+		}
+		time.Sleep(5 * time.Millisecond)
+	}
+	t.Fatal("latest pending frame was not delivered")
+}