fix(flutter): 增加剧场搜索清空按钮

test/discover/discover_search_field_test.dart

@@ -0,0 +1,57 @@
+// Author: fruit.com.cn
+
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:fruitshorts/l10n/app_localizations.dart';
+import 'package:fruitshorts/pages/discover/widgets/discover_search_field.dart';
+
+void main() {
+  testWidgets('should_clear_text_and_keep_focus_when_clear_is_tapped', (
+    tester,
+  ) async {
+    final controller = TextEditingController();
+    final focusNode = FocusNode();
+    final changes = <String>[];
+    addTearDown(controller.dispose);
+    addTearDown(focusNode.dispose);
+
+    await tester.pumpWidget(
+      MaterialApp(
+        locale: const Locale('en'),
+        localizationsDelegates: AppLocalizations.localizationsDelegates,
+        supportedLocales: AppLocalizations.supportedLocales,
+        home: Scaffold(
+          body: DiscoverSearchField(
+            controller: controller,
+            focusNode: focusNode,
+            onChanged: changes.add,
+            loading: true,
+          ),
+        ),
+      ),
+    );
+
+    final search = find.byKey(const Key('discover-search'));
+    expect(find.byKey(const Key('discover-search-clear')), findsNothing);
+
+    await tester.tap(search);
+    await tester.enterText(search, 'velvet');
+    await tester.pump();
+    changes.clear();
+
+    final clear = find.byKey(const Key('discover-search-clear'));
+    final loading = find.byKey(const Key('discover-search-loading'));
+    expect(clear, findsOneWidget);
+    expect(loading, findsOneWidget);
+    expect(tester.getSize(clear), const Size(18, 18));
+    expect(tester.getRect(loading).right, lessThan(tester.getRect(clear).left));
+
+    await tester.tap(clear);
+    await tester.pump();
+
+    expect(controller.text, isEmpty);
+    expect(changes, ['']);
+    expect(find.byKey(const Key('discover-search-clear')), findsNothing);
+    expect(focusNode.hasFocus, isTrue);
+  });
+}