fix(authenticator): date validator

packages/authenticator/amplify_authenticator/lib/src/widgets/form_fields/sign_up_form_field.dart

@@ -780,6 +780,9 @@ class _SignUpDateFieldState extends _SignUpFormFieldState<String>
 
   @override
   FormFieldValidator<String> get validator {
+    if (widget.validatorOverride != null) {
+      return widget.validatorOverride!;
+    }
     return simpleValidator(
       stringResolver.inputs.resolve(
         context,

packages/authenticator/amplify_authenticator/test/sign_up_form_test.dart

@@ -73,6 +73,53 @@ void main() {
         },
       );
 
+      testWidgets(
+        'displays message when submitted with invalid birth date',
+        (tester) async {
+          await tester.pumpWidget(
+            MockAuthenticatorApp(
+              initialStep: AuthenticatorStep.signUp,
+              signUpForm: SignUpForm.custom(
+                fields: [
+                  SignUpFormField.username(),
+                  SignUpFormField.birthdate(
+                    validator: (value) {
+                      if (value == null || value.isEmpty) return null;
+                      final age = DateTime.now().difference(
+                        DateTime.parse(value),
+                      );
+                      if (age < const Duration(days: 365 * 18)) {
+                        return 'You must be 18 years or older.';
+                      }
+                      return null;
+                    },
+                  ),
+                  SignUpFormField.password(),
+                  SignUpFormField.passwordConfirmation(),
+                ],
+              ),
+            ),
+          );
+          await tester.pumpAndSettle();
+
+          final signUpPage = SignUpPage(tester: tester);
+
+          await signUpPage.enterUsername('user123');
+          await signUpPage.enterBirthDate('01/01/2020');
+          await signUpPage.enterPassword('Password123');
+          await signUpPage.enterPasswordConfirmation('Password123');
+
+          await signUpPage.submitSignUp();
+
+          final usernameFieldError = find.descendant(
+            of: signUpPage.birthdateField,
+            matching: find.text('You must be 18 years or older.'),
+          );
+
+          expect(usernameFieldError, findsOneWidget);
+        },
+      );
+
       testWidgets(
         'displays message when password does not meet requirements',
         (tester) async {

packages/authenticator/amplify_authenticator_test/lib/src/mock_authenticator_app.dart

@@ -22,6 +22,8 @@ class MockAuthenticatorApp extends StatefulWidget {
     this.darkTheme,
     this.initialStep = AuthenticatorStep.signIn,
     this.authPlugin,
+    this.signInForm,
+    this.signUpForm,
     this.child,
   });
 
@@ -30,6 +32,8 @@ class MockAuthenticatorApp extends StatefulWidget {
   final ThemeData? darkTheme;
   final AuthenticatorStep initialStep;
   final AuthPluginInterface? authPlugin;
+  final SignInForm? signInForm;
+  final SignUpForm? signUpForm;
   final Widget? child;
 
   @override
@@ -102,6 +106,8 @@ class _MockAuthenticatorAppState extends State<MockAuthenticatorApp> {
     return Authenticator(
       key: authenticatorKey,
       authBlocOverride: _authBloc,
+      signInForm: widget.signInForm,
+      signUpForm: widget.signUpForm,
       child: widget.child ??
           MaterialApp(
             debugShowCheckedModeBanner: false,

packages/authenticator/amplify_authenticator_test/lib/src/pages/sign_up_page.dart

@@ -21,6 +21,15 @@ class SignUpPage extends AuthenticatorPage {
   Finder get phoneField => find.byKey(keyPhoneNumberSignUpFormField);
   Finder get preferredUsernameField =>
       find.byKey(keyPreferredUsernameSignUpFormField);
+  Finder get birthdateField => find.byKey(keyBirthdateSignUpFormField);
+  Finder get datePickerTextField => find.descendant(
+        of: find.byType(InputDatePickerFormField),
+        matching: find.byType(TextFormField),
+      );
+  Finder get datePickerOkayButton => find.descendant(
+        of: find.byType(DatePickerDialog),
+        matching: find.byType(TextButton).at(1),
+      );
   Finder get signUpButton => find.byKey(keySignUpButton);
 
   Finder get selectEmailButton => find.byKey(keyEmailUsernameToggleButton);
@@ -67,6 +76,16 @@ class SignUpPage extends AuthenticatorPage {
     await tester.enterText(preferredUsernameField, username);
   }
 
+  /// When I type a new "birth date"
+  Future<void> enterBirthDate(String value) async {
+    await tester.ensureVisible(birthdateField);
+    await tester.tap(birthdateField);
+    await tester.pumpAndSettle();
+    await tester.enterText(datePickerTextField, value);
+    await tester.tap(datePickerOkayButton);
+    await tester.pumpAndSettle();
+  }
+
   /// When I click the "Create Account" button
   Future<void> submitSignUp() async {
     await tester.ensureVisible(signUpButton);