evision-safe playlist timing

internal/playback/playlist_timing_test.go

@@ -0,0 +1,119 @@
+package playback
+
+import (
+	"testing"
+	"time"
+)
+
+func TestNewPlaylistTimingResetsState(t *testing.T) {
+	got := NewPlaylistTiming(7, 10*time.Second)
+	want := PlaylistTimingState{Revision: 7, Duration: 10 * time.Second}
+	if got != want {
+		t.Fatalf("NewPlaylistTiming() = %#v, want %#v", got, want)
+	}
+}
+
+func TestStartPlaylistTiming(t *testing.T) {
+	now := time.Date(2026, time.September, 1, 12, 0, 0, 0, time.UTC)
+	current := NewPlaylistTiming(4, 10*time.Second)
+
+	got, started := StartPlaylistTiming(current, 4, now)
+	if !started {
+		t.Fatal("StartPlaylistTiming() started = false, want true")
+	}
+	want := PlaylistTimingState{
+		Revision: 4,
+		Duration: 10 * time.Second,
+		Started:  true,
+		Deadline: now.Add(10 * time.Second),
+	}
+	if got != want {
+		t.Fatalf("StartPlaylistTiming() = %#v, want %#v", got, want)
+	}
+}
+
+func TestStartPlaylistTimingIgnoresInapplicableReadiness(t *testing.T) {
+	now := time.Date(2026, time.September, 1, 12, 0, 0, 0, time.UTC)
+	started, ok := StartPlaylistTiming(NewPlaylistTiming(4, time.Second), 4, now)
+	if !ok {
+		t.Fatal("initial StartPlaylistTiming() did not start")
+	}
+	tests := []struct {
+		name     string
+		current  PlaylistTimingState
+		revision uint64
+	}{
+		{name: "zero duration", current: NewPlaylistTiming(4, 0), revision: 4},
+		{name: "stale revision", current: NewPlaylistTiming(4, time.Second), revision: 3},
+		{name: "future revision", current: NewPlaylistTiming(4, time.Second), revision: 5},
+		{name: "already started", current: started, revision: 4},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			got, changed := StartPlaylistTiming(test.current, test.revision, now.Add(time.Second))
+			if changed {
+				t.Fatal("StartPlaylistTiming() changed = true, want false")
+			}
+			if got != test.current {
+				t.Fatalf("StartPlaylistTiming() = %#v, want unchanged %#v", got, test.current)
+			}
+		})
+	}
+}
+
+func TestExpirePlaylistTiming(t *testing.T) {
+	now := time.Date(2026, time.September, 1, 12, 0, 0, 0, time.UTC)
+	current, _ := StartPlaylistTiming(NewPlaylistTiming(9, 5*time.Second), 9, now)
+
+	got, expired := ExpirePlaylistTiming(current, 9, now.Add(5*time.Second))
+	if !expired {
+		t.Fatal("ExpirePlaylistTiming() expired = false, want true")
+	}
+	want := PlaylistTimingState{Revision: 9, Duration: 5 * time.Second}
+	if got != want {
+		t.Fatalf("ExpirePlaylistTiming() = %#v, want %#v", got, want)
+	}
+
+	again, expired := ExpirePlaylistTiming(got, 9, now.Add(6*time.Second))
+	if expired || again != got {
+		t.Fatalf("duplicate ExpirePlaylistTiming() = %#v, %v; want unchanged, false", again, expired)
+	}
+}
+
+func TestExpirePlaylistTimingIgnoresInapplicableEvents(t *testing.T) {
+	now := time.Date(2026, time.September, 1, 12, 0, 0, 0, time.UTC)
+	current, _ := StartPlaylistTiming(NewPlaylistTiming(4, 10*time.Second), 4, now)
+	tests := []struct {
+		name     string
+		revision uint64
+		at       time.Time
+	}{
+		{name: "early", revision: 4, at: now.Add(9 * time.Second)},
+		{name: "stale revision", revision: 3, at: now.Add(10 * time.Second)},
+		{name: "future revision", revision: 5, at: now.Add(10 * time.Second)},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			got, expired := ExpirePlaylistTiming(current, test.revision, test.at)
+			if expired {
+				t.Fatal("ExpirePlaylistTiming() expired = true, want false")
+			}
+			if got != current {
+				t.Fatalf("ExpirePlaylistTiming() = %#v, want unchanged %#v", got, current)
+			}
+		})
+	}
+}
+
+func TestNewPlaylistTimingInvalidatesPreviousDeadline(t *testing.T) {
+	now := time.Date(2026, time.September, 1, 12, 0, 0, 0, time.UTC)
+	old, _ := StartPlaylistTiming(NewPlaylistTiming(1, time.Second), 1, now)
+	current := NewPlaylistTiming(2, 2*time.Second)
+
+	got, expired := ExpirePlaylistTiming(current, old.Revision, old.Deadline)
+	if expired || got != current {
+		t.Fatalf("old expiry changed new timing: %#v, %v", got, expired)
+	}
+}