fixed guardian login edge cases and misleading placeholders on failed loads

test/view/login/guardian_login_controller_test.dart

@@ -220,6 +220,45 @@ void main() {
     expect(signedIn.single.isDemo, isTrue);
   });
 
+  test('a failing demo sign-in reports instead of throwing', () async {
+    final c = GuardianLoginController(
+      request: request,
+      verify: verify,
+      store: store,
+      signIn: (_) async => throw Exception('keystore unavailable'),
+      tokenName: () async => 'test',
+      now: () => now,
+    );
+    expect(await c.requestCode(DemoMode.guardianEmail), isFalse);
+    expect(c.errorMessage, isNotNull);
+    expect(c.loading, isFalse);
+  });
+
+  test('a code without a running request reports instead of failing '
+      'silently', () async {
+    final c = controller();
+    expect(await c.submitCode('123456'), isFalse);
+    expect(c.errorMessage, isNotNull);
+    expect(c.step, GuardianLoginStep.enterEmail);
+    expect(verify.lastCall, isNull);
+  });
+
+  test('a link of another server is named as such', () {
+    final c = controller();
+    c.rejectForeignLink();
+    expect(c.errorMessage, contains('anderen Server'));
+  });
+
+  test('the resend cooldown runs on the injected clock', () async {
+    final c = controller();
+    await c.requestCode('e@x.de');
+    expect(c.resendCooldown(), const Duration(seconds: 60));
+    expect(c.canResend(), isFalse);
+    now = now.add(const Duration(seconds: 61));
+    expect(c.resendCooldown(), Duration.zero);
+    expect(c.canResend(), isTrue);
+  });
+
   group('GuardianLoginException.fromDio', () {
     DioException failure(int status, Object? body) => DioException(
       requestOptions: RequestOptions(),
@@ -291,6 +330,17 @@ void main() {
       expect(e.error, GuardianLoginError.accountDisabled);
     });
 
+    test('a bare 401 on the e-mail step is not a wrong code', () {
+      expect(
+        GuardianLoginException.fromDio(failure(401, null), verifying: false),
+        isNot(isA<GuardianLoginException>()),
+      );
+      final verifying =
+          GuardianLoginException.fromDio(failure(401, null))
+              as GuardianLoginException;
+      expect(verifying.error, GuardianLoginError.invalidCode);
+    });
+
     test('server errors keep the generic mapping', () {
       expect(
         GuardianLoginException.fromDio(failure(500, 'boom')),

test/view/parent_letters/parent_letter_form_policy_test.dart

@@ -75,13 +75,22 @@ void main() {
       expect(policy.mode, ParentLetterFormMode.done);
     });
 
-    test('unknown optional fields are skipped', () {
+    test('unknown optional fields are skipped but flagged', () {
       final policy = ParentLetterFormPolicy.resolve(
         request: const ParentLetterRequest(fields: [_choice, _unknownOptional]),
         child: _child(),
       )!;
       expect(policy.mode, ParentLetterFormMode.open);
       expect(policy.fields, [_choice]);
+      expect(policy.hasUnsupportedFields, isTrue);
+    });
+
+    test('a fully supported request is not flagged', () {
+      final policy = ParentLetterFormPolicy.resolve(
+        request: const ParentLetterRequest(fields: [_choice, _optionalChoice]),
+        child: _child(),
+      )!;
+      expect(policy.hasUnsupportedFields, isFalse);
     });
   });