evision-safe playlist timing

internal/playback/playlist_controller_test.go

@@ -257,6 +257,58 @@ func TestPlaylistControllerSnapshotConcurrentReads(t *testing.T) {
 	}
 }
 
+func TestPlaylistControllerSnapshotRevision(t *testing.T) {
+	controller, commands, sessions, cancel, result := startPlaylistController(t, navigationPlaylist(false), 8)
+	defer cancel()
+
+	initial := waitForPlaylistSnapshot(t, controller, func(snapshot PlaylistSnapshot) bool {
+		return !snapshot.State.HasSelection
+	})
+	if initial.Revision != 0 {
+		t.Fatalf("initial revision = %d, want 0", initial.Revision)
+	}
+
+	commands <- PlaylistCommand{Kind: PlaylistSelect, Index: 1}
+	_ = receivePlaylistSession(t, sessions)
+	selected := waitForPlaylistSnapshot(t, controller, func(snapshot PlaylistSnapshot) bool {
+		return snapshot.Revision == 1
+	})
+	if selected.State.CurrentIndex != 1 {
+		t.Fatalf("selected state = %#v, want index 1", selected.State)
+	}
+
+	commands <- PlaylistCommand{Kind: PlaylistSelect, Index: 1}
+	_ = receivePlaylistSession(t, sessions)
+	waitForPlaylistSnapshot(t, controller, func(snapshot PlaylistSnapshot) bool {
+		return snapshot.Revision == 2
+	})
+
+	commands <- PlaylistCommand{Kind: PlaylistSelect, Index: 2}
+	_ = receivePlaylistSession(t, sessions)
+	waitForPlaylistSnapshot(t, controller, func(snapshot PlaylistSnapshot) bool {
+		return snapshot.Revision == 3
+	})
+
+	commands <- PlaylistCommand{Kind: PlaylistNext}
+	time.Sleep(time.Millisecond)
+	boundary, ok := controller.Snapshot()
+	if !ok || boundary.Revision != 3 {
+		t.Fatalf("boundary snapshot = %#v, %v; want revision 3", boundary, ok)
+	}
+
+	commands <- PlaylistCommand{}
+	time.Sleep(time.Millisecond)
+	invalid, ok := controller.Snapshot()
+	if !ok || invalid.Revision != 3 {
+		t.Fatalf("invalid-command snapshot = %#v, %v; want revision 3", invalid, ok)
+	}
+
+	close(commands)
+	if err := waitForPlaylistResult(t, result); err != nil {
+		t.Fatalf("Run() error = %v", err)
+	}
+}
+
 func startPlaylistController(
 	t *testing.T,
 	playlist Playlist,