OIDC로 빠지는 분기 점검 login_challenge 복구 fallback 추가

userfront/test/login_challenge_resolver_test.dart

@@ -0,0 +1,69 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:userfront/features/auth/domain/login_challenge_resolver.dart';
+
+void main() {
+  group('login_challenge_resolver', () {
+    test('widget 값이 있으면 최우선으로 사용', () {
+      final resolved = resolveLoginChallenge(
+        widgetLoginChallenge: 'widget-challenge',
+        uri: Uri.parse('/ko/login'),
+        rawSearch: '?login_challenge=raw-search',
+        rawHref: 'https://sso-test.hmac.kr/ko/login?login_challenge=raw-href',
+      );
+
+      expect(resolved.value, 'widget-challenge');
+      expect(resolved.source, LoginChallengeSource.widget);
+    });
+
+    test('widget 값이 없으면 URI query에서 복구', () {
+      final resolved = resolveLoginChallenge(
+        widgetLoginChallenge: null,
+        uri: Uri.parse('/ko/login?login_challenge=uri-query'),
+        rawSearch: '',
+        rawHref: '',
+      );
+
+      expect(resolved.value, 'uri-query');
+      expect(resolved.source, LoginChallengeSource.uriQuery);
+    });
+
+    test('URI query가 비어 있으면 raw search에서 복구', () {
+      final resolved = resolveLoginChallenge(
+        widgetLoginChallenge: null,
+        uri: Uri.parse('/ko/login'),
+        rawSearch: '?login_challenge=raw-search-value&x=1',
+        rawHref: '',
+      );
+
+      expect(resolved.value, 'raw-search-value');
+      expect(resolved.source, LoginChallengeSource.rawSearch);
+      expect(resolved.rawSearchHasLoginChallenge, isTrue);
+    });
+
+    test('raw search도 비어 있으면 raw href에서 복구', () {
+      final resolved = resolveLoginChallenge(
+        widgetLoginChallenge: null,
+        uri: Uri.parse('/ko/login'),
+        rawSearch: '',
+        rawHref:
+            'https://sso-test.hmac.kr/ko/login?a=1&login_challenge=raw-href-value#fragment',
+      );
+
+      expect(resolved.value, 'raw-href-value');
+      expect(resolved.source, LoginChallengeSource.rawHref);
+      expect(resolved.rawHrefHasLoginChallenge, isTrue);
+    });
+
+    test('값이 전부 없으면 missing', () {
+      final resolved = resolveLoginChallenge(
+        widgetLoginChallenge: null,
+        uri: Uri.parse('/ko/login'),
+        rawSearch: '',
+        rawHref: 'https://sso-test.hmac.kr/ko/login?x=1',
+      );
+
+      expect(resolved.value, isNull);
+      expect(resolved.source, LoginChallengeSource.missing);
+    });
+  });
+}

userfront/test/router_redirect_widget_test.dart

@@ -28,6 +28,21 @@ Widget _buildTestApp(String initialLocation) {
               );
             },
           ),
+          GoRoute(
+            path: 'login',
+            builder: (context, state) {
+              final challenge = state.uri.queryParameters['login_challenge'];
+              final redirect =
+                  state.uri.queryParameters['redirect_uri'] ??
+                  state.uri.queryParameters['redirect_url'] ??
+                  '';
+              return Scaffold(
+                body: Text(
+                  'login|challenge=${challenge ?? ''}|redirect=$redirect',
+                ),
+              );
+            },
+          ),
           GoRoute(
             path: 'profile',
             builder: (context, state) =>
@@ -45,7 +60,7 @@ Widget _buildTestApp(String initialLocation) {
       final isLoggedIn =
           AuthTokenStore.getToken() != null || AuthTokenStore.usesCookie();
       final path = stripLocalePath(state.uri);
-      final isPublicPath = path == '/signin';
+      final isPublicPath = path == '/signin' || path == '/login';
       if (isPublicPath) {
         return null;
       }
@@ -70,6 +85,25 @@ void main() {
     LocaleRegistry.resetForTest();
   });
 
+  testWidgets('/login: login_challenge와 redirect_uri를 전달', (tester) async {
+    final encodedRedirectUri = Uri.encodeComponent(
+      'https://rp.example.com/callback?x=1',
+    );
+    await tester.pumpWidget(
+      _buildTestApp(
+        '/en/login?login_challenge=lc_999&redirect_uri=$encodedRedirectUri',
+      ),
+    );
+    await tester.pumpAndSettle();
+
+    expect(
+      find.text(
+        'login|challenge=lc_999|redirect=https://rp.example.com/callback?x=1',
+      ),
+      findsOneWidget,
+    );
+  });
+
   testWidgets('비로그인: redirect_uri/login_challenge가 signin으로 전달', (
     tester,
   ) async {