feat(app): 增加首页榜单 tab

test/ranking/ranking_logic_test.dart

@@ -0,0 +1,74 @@
+// Author: fruit.com.cn
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:fruitshorts/core/data/models/drama.dart';
+import 'package:fruitshorts/core/data/models/home_feed.dart';
+import 'package:fruitshorts/pages/ranking/ranking_logic.dart';
+
+void main() {
+  test('should_use_backend_hot_order_when_hot_board_is_selected', () {
+    final logic = RankingLogic(
+      sections: [
+        FeedSection(
+          code: 'hot',
+          title: 'Hot',
+          dramas: [_drama('first'), _drama('second')],
+        ),
+        FeedSection(code: 'new', title: 'New', dramas: [_drama('fresh')]),
+      ],
+      fallback: [_drama('fallback')],
+    );
+
+    expect(logic.board, RankingBoard.hot);
+    expect(logic.entries.map((entry) => entry.drama.id), ['first', 'second']);
+    expect(logic.entries.map((entry) => entry.rank), [1, 2]);
+    logic.dispose();
+  });
+
+  test('should_switch_to_new_releases_when_new_board_is_selected', () {
+    final logic = RankingLogic(
+      sections: [
+        FeedSection(code: 'hot', title: 'Hot', dramas: [_drama('hot')]),
+        FeedSection(code: 'new', title: 'New', dramas: [_drama('fresh')]),
+      ],
+      fallback: const [],
+    );
+
+    logic.select(RankingBoard.newReleases);
+
+    expect(logic.board, RankingBoard.newReleases);
+    expect(logic.entries.single.drama.id, 'fresh');
+    logic.dispose();
+  });
+
+  test(
+    'should_deduplicate_and_fall_back_when_requested_section_is_missing',
+    () {
+      final logic = RankingLogic(
+        sections: [
+          FeedSection(
+            code: 'hot',
+            title: 'Hot',
+            dramas: [_drama('a'), _drama('a')],
+          ),
+        ],
+        fallback: [_drama('b'), _drama('a')],
+      );
+
+      expect(logic.entries.map((entry) => entry.drama.id), ['a']);
+
+      logic.select(RankingBoard.newReleases);
+
+      expect(logic.entries.map((entry) => entry.drama.id), ['b', 'a']);
+      expect(logic.entries.last.rank, 2);
+      logic.dispose();
+    },
+  );
+}
+
+Drama _drama(String id) => Drama(
+  id: id,
+  title: 'Drama $id',
+  synopsis: 'Synopsis $id',
+  posterUrl: '/files/$id.jpg',
+);