feat(player): 未就绪改由进度条展示加载态

test/player/loading_progress_track_test.dart

@@ -0,0 +1,53 @@
+// Author: fruit.com.cn
+
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import 'package:fruitshorts/core/theme/app_colors.dart';
+import 'package:fruitshorts/pages/player/widgets/loading_progress_track.dart';
+
+void main() {
+  testWidgets('should_move_highlight_while_loading', (tester) async {
+    tester.binding.handleAppLifecycleStateChanged(AppLifecycleState.resumed);
+    addTearDown(
+      () => tester.binding.handleAppLifecycleStateChanged(
+        AppLifecycleState.paused,
+      ),
+    );
+    await tester.pumpWidget(
+      const MaterialApp(
+        home: Scaffold(
+          body: Center(
+            child: SizedBox(width: 240, child: LoadingProgressTrack(height: 4)),
+          ),
+        ),
+      ),
+    );
+
+    expect(find.byKey(const Key('progress-loading')), findsOneWidget);
+    expect(
+      tester
+          .widget<ColoredBox>(find.byKey(const Key('progress-loading-track')))
+          .color,
+      Colors.white24,
+    );
+    expect(
+      tester
+          .widget<ColoredBox>(
+            find.byKey(const Key('progress-loading-highlight')),
+          )
+          .color,
+      AppColors.blue,
+    );
+
+    final initialLeft = tester
+        .getTopLeft(find.byKey(const Key('progress-loading-highlight')))
+        .dx;
+    await tester.pump(const Duration(milliseconds: 300));
+    final movedLeft = tester
+        .getTopLeft(find.byKey(const Key('progress-loading-highlight')))
+        .dx;
+    expect(movedLeft, greaterThan(initialLeft));
+    expect(tester.getSize(find.byKey(const Key('progress-loading'))).height, 4);
+  });
+}