fix(player): 修复竖滑上一集不自动播放

test/player/player_fullscreen_test.dart

@@ -50,7 +50,11 @@ void main() {
           .homeMode,
       isTrue,
     );
-    expect(find.byType(PageView), findsOneWidget);
+    final pageViews = tester.widgetList<PageView>(find.byType(PageView));
+    expect(
+      pageViews.where((pageView) => pageView.scrollDirection == Axis.vertical),
+      hasLength(1),
+    );
     expect(tester.takeException(), isNull);
   });
 

test/player/player_opening_frame_test.dart

@@ -16,10 +16,17 @@ sprite_001.jpg#xywh=0,0,160,90
 
 void main() {
   test('should_return_no_opening_frame_when_thumbnails_url_is_empty', () {
-    expect(playerOpeningFrame(null), isNull);
+    expect(playerOpeningFrame(null, posterUrl: '  '), isNull);
     expect(playerOpeningFrame('  '), isNull);
   });
 
+  test('should_keep_opening_frame_when_only_poster_is_available', () {
+    expect(
+      playerOpeningFrame(null, posterUrl: 'https://cdn.test/poster.jpg'),
+      isA<PlayerOpeningFrame>(),
+    );
+  });
+
   testWidgets('should_load_and_reuse_first_sprite_frame', (tester) async {
     final loader = _FakeSpriteLoader();
     final cache = OpeningFrameCache();
@@ -58,6 +65,24 @@ void main() {
 
     expect(find.byKey(const Key('player-opening-sprite')), findsOneWidget);
   });
+
+  testWidgets('should_show_poster_while_sprite_is_loading', (tester) async {
+    final cache = OpeningFrameCache();
+    addTearDown(cache.clear);
+
+    await tester.pumpWidget(
+      MaterialApp(
+        home: PlayerOpeningFrame(
+          thumbnailsUrl: 'https://cdn.test/thumbnails.vtt',
+          posterUrl: 'https://cdn.test/poster.jpg',
+          loader: _FakeSpriteLoader(),
+          cache: cache,
+        ),
+      ),
+    );
+
+    expect(find.byKey(const Key('player-opening-poster')), findsOneWidget);
+  });
 }
 
 class _FakeSpriteLoader implements SpriteThumbnailAssetLoader {