feat: 결재·마스터 실연동 업데이트

test/features/util/postal_search/presentation/widgets/postal_search_dialog_test.dart

@@ -2,6 +2,8 @@ import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:shadcn_ui/shadcn_ui.dart';
 
+import 'package:superport_v2/core/network/api_error.dart';
+import 'package:superport_v2/core/network/failure.dart';
 import 'package:superport_v2/features/util/postal_search/presentation/models/postal_search_result.dart';
 import 'package:superport_v2/features/util/postal_search/presentation/widgets/postal_search_dialog.dart';
 
@@ -151,4 +153,32 @@ void main() {
     await tester.tap(find.text('닫기'));
     await tester.pumpAndSettle();
   });
+
+  testWidgets('검색 실패 시 Failure 메시지를 표시한다', (tester) async {
+    final exception = ApiException(
+      code: ApiErrorCode.unprocessableEntity,
+      message: '우편번호 검색에 실패했습니다.',
+      details: {
+        'errors': {
+          'keyword': ['검색어를 다시 확인해 주세요.'],
+        },
+      },
+    );
+
+    await tester.pumpWidget(
+      _PostalSearchHarness(
+        fetcher: (_) => Future<List<PostalSearchResult>>.error(exception),
+      ),
+    );
+
+    await tester.pumpAndSettle();
+
+    final inputFinder = find.byType(EditableText);
+    await tester.enterText(inputFinder, '강남대로');
+    await tester.tap(find.text('검색'));
+    await tester.pumpAndSettle();
+
+    final failure = Failure.from(exception);
+    expect(find.text(failure.describe()), findsOneWidget);
+  });
 }