Add suggestion for From/To dialog when input is new email address

test/features/base/mixin/auto_complete_result_mixin_test.dart

@@ -0,0 +1,59 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:jmap_dart_client/jmap/mail/email/email_address.dart';
+import 'package:tmail_ui_user/features/base/mixin/auto_complete_result_mixin.dart';
+import 'package:tmail_ui_user/features/composer/domain/state/get_autocomplete_state.dart';
+import 'package:tmail_ui_user/features/composer/domain/state/get_device_contact_suggestions_state.dart';
+
+class AutoCompleteResult with AutoCompleteResultMixin {}
+
+void main() {
+  late AutoCompleteResult autoCompleteResult;
+
+  setUp(() {
+    autoCompleteResult = AutoCompleteResult();
+  });
+
+  group('handleAutoCompleteSuccess::test', () {
+    test('SHOULD return list of EmailAddress from GetAutoCompleteSuccess', () {
+      final mockEmailAddress = EmailAddress('Test User', 'test@example.com');
+      final success = GetAutoCompleteSuccess([mockEmailAddress]);
+      final result = autoCompleteResult.handleAutoCompleteSuccess(success, 'query');
+
+      expect(result, [mockEmailAddress]);
+    });
+
+    test('SHOULD return list of EmailAddress from GetDeviceContactSuggestionsSuccess', () {
+      final mockEmailAddress = EmailAddress('Contact User', 'contact@example.com');
+      final success = GetDeviceContactSuggestionsSuccess([mockEmailAddress]);
+      final result = autoCompleteResult.handleAutoCompleteSuccess(success, 'query');
+
+      expect(result, [mockEmailAddress]);
+    });
+
+    test('SHOULD return query email address if list is empty and query is a valid email', () {
+      final success = GetAutoCompleteSuccess([]);
+      final result = autoCompleteResult.handleAutoCompleteSuccess(success, 'newemail@example.com');
+
+      expect(result, [EmailAddress('newemail@example.com', 'newemail@example.com')]);
+    });
+
+    test('SHOULD add query email address to the start if not present and is a valid email', () {
+      final mockEmailAddress = EmailAddress('Existing User', 'existing@example.com');
+      final success = GetAutoCompleteSuccess([mockEmailAddress]);
+      final result = autoCompleteResult.handleAutoCompleteSuccess(success, 'newemail@example.com');
+
+      expect(result, [
+        EmailAddress('newemail@example.com', 'newemail@example.com'),
+        mockEmailAddress
+      ]);
+    });
+
+    test('SHOULD not add query email address if already present', () {
+      final mockEmailAddress = EmailAddress('Existing User', 'existing@example.com');
+      final success = GetAutoCompleteSuccess([mockEmailAddress]);
+      final result = autoCompleteResult.handleAutoCompleteSuccess(success, 'existing@example.com');
+
+      expect(result, [mockEmailAddress]);
+    });
+  });
+}