diff --git a/test/features/base/mixin/parse_error_for_set_response_test.dart b/test/features/base/mixin/parse_error_for_set_response_test.dart
new file mode 100644
index 000000000..ade201198
--- /dev/null
+++ b/test/features/base/mixin/parse_error_for_set_response_test.dart
@@ -0,0 +1,336 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:jmap_dart_client/jmap/account_id.dart';
+import 'package:jmap_dart_client/jmap/core/error/method/error_method_response.dart';
+import 'package:jmap_dart_client/jmap/core/error/set_error.dart';
+import 'package:jmap_dart_client/jmap/core/id.dart';
+import 'package:labels/method/set/set_label_response.dart';
+import 'package:tmail_ui_user/features/base/mixin/handle_error_mixin.dart';
+
+class TestSetErrorHandler with HandleSetErrorMixin {}
+
+void main() {
+  late TestSetErrorHandler testHandler;
+
+  setUp(() {
+    testHandler = TestSetErrorHandler();
+  });
+
+  group('HandleSetErrorMixin::parseErrorForSetResponse', () {
+    final requestId = Id('request-123');
+    final accountId = AccountId(Id('account-1'));
+
+    test('should throw InvalidArgumentsMethodResponse when error type is invalidArguments in notCreated', () {
+      // Arrange
+      final setError = SetError(ErrorMethodResponse.invalidArguments);
+      final response = SetLabelResponse(
+        accountId,
+        notCreated: {requestId: setError},
+      );
+
+      // Act & Assert
+      expect(
+        () => testHandler.parseErrorForSetResponse(response, requestId),
+        throwsA(isA<InvalidArgumentsMethodResponse>()),
+      );
+    });
+
+    test('should throw InvalidArgumentsMethodResponse with description when provided', () {
+      // Arrange
+      final setError = SetError(
+        ErrorMethodResponse.invalidArguments,
+        description: 'Label name cannot be empty',
+      );
+      final response = SetLabelResponse(
+        accountId,
+        notCreated: {requestId: setError},
+      );
+
+      // Act & Assert
+      expect(
+        () => testHandler.parseErrorForSetResponse(response, requestId),
+        throwsA(
+          isA<InvalidArgumentsMethodResponse>().having(
+            (e) => e.description,
+            'description',
+            'Label name cannot be empty',
+          ),
+        ),
+      );
+    });
+
+    test('should throw InvalidArgumentsMethodResponse when error type is invalidArguments in notUpdated', () {
+      // Arrange
+      final setError = SetError(ErrorMethodResponse.invalidArguments);
+      final response = SetLabelResponse(
+        accountId,
+        notUpdated: {requestId: setError},
+      );
+
+      // Act & Assert
+      expect(
+        () => testHandler.parseErrorForSetResponse(response, requestId),
+        throwsA(isA<InvalidArgumentsMethodResponse>()),
+      );
+    });
+
+    test('should throw InvalidArgumentsMethodResponse when error type is invalidArguments in notDestroyed', () {
+      // Arrange
+      final setError = SetError(ErrorMethodResponse.invalidArguments);
+      final response = SetLabelResponse(
+        accountId,
+        notDestroyed: {requestId: setError},
+      );
+
+      // Act & Assert
+      expect(
+        () => testHandler.parseErrorForSetResponse(response, requestId),
+        throwsA(isA<InvalidArgumentsMethodResponse>()),
+      );
+    });
+
+    test('should throw InvalidResultReferenceMethodResponse when error type is invalidResultReference', () {
+      // Arrange
+      final setError = SetError(ErrorMethodResponse.invalidResultReference);
+      final response = SetLabelResponse(
+        accountId,
+        notCreated: {requestId: setError},
+      );
+
+      // Act & Assert
+      expect(
+        () => testHandler.parseErrorForSetResponse(response, requestId),
+        throwsA(isA<InvalidResultReferenceMethodResponse>()),
+      );
+    });
+
+    test('should throw InvalidResultReferenceMethodResponse with description when provided', () {
+      // Arrange
+      final setError = SetError(
+        ErrorMethodResponse.invalidResultReference,
+        description: 'Invalid reference to previous result',
+      );
+      final response = SetLabelResponse(
+        accountId,
+        notCreated: {requestId: setError},
+      );
+
+      // Act & Assert
+      expect(
+        () => testHandler.parseErrorForSetResponse(response, requestId),
+        throwsA(
+          isA<InvalidResultReferenceMethodResponse>().having(
+            (e) => e.description,
+            'description',
+            'Invalid reference to previous result',
+          ),
+        ),
+      );
+    });
+
+    test('should throw UnknownMethodResponse when error type is not recognized', () {
+      // Arrange
+      final setError = SetError(ErrorMethodResponse.serverFail);
+      final response = SetLabelResponse(
+        accountId,
+        notCreated: {requestId: setError},
+      );
+
+      // Act & Assert
+      expect(
+        () => testHandler.parseErrorForSetResponse(response, requestId),
+        throwsA(isA<UnknownMethodResponse>()),
+      );
+    });
+
+    test('should throw UnknownMethodResponse with description when error type is unknown', () {
+      // Arrange
+      final setError = SetError(
+        ErrorMethodResponse.serverFail,
+        description: 'Internal server error',
+      );
+      final response = SetLabelResponse(
+        accountId,
+        notCreated: {requestId: setError},
+      );
+
+      // Act & Assert
+      expect(
+        () => testHandler.parseErrorForSetResponse(response, requestId),
+        throwsA(
+          isA<UnknownMethodResponse>().having(
+            (e) => e.description,
+            'description',
+            'Internal server error',
+          ),
+        ),
+      );
+    });
+
+    test('should throw UnknownMethodResponse when requestId is not found in error map', () {
+      // Arrange
+      final differentId = Id('different-request');
+      final setError = SetError(ErrorMethodResponse.invalidArguments);
+      final response = SetLabelResponse(
+        accountId,
+        notCreated: {differentId: setError},
+      );
+
+      // Act & Assert
+      expect(
+        () => testHandler.parseErrorForSetResponse(response, requestId),
+        throwsA(isA<UnknownMethodResponse>()),
+      );
+    });
+
+    test('should throw UnknownMethodResponse without description when requestId not found', () {
+      // Arrange
+      final response = SetLabelResponse(accountId);
+
+      // Act & Assert
+      expect(
+        () => testHandler.parseErrorForSetResponse(response, requestId),
+        throwsA(
+          isA<UnknownMethodResponse>().having(
+            (e) => e.description,
+            'description',
+            isNull,
+          ),
+        ),
+      );
+    });
+
+    test('should check all error maps (notCreated, notUpdated, notDestroyed)', () {
+      // Arrange - error in notUpdated
+      final setError = SetError(ErrorMethodResponse.invalidArguments);
+      final response = SetLabelResponse(
+        accountId,
+        notUpdated: {requestId: setError},
+      );
+
+      // Act & Assert
+      expect(
+        () => testHandler.parseErrorForSetResponse(response, requestId),
+        throwsA(isA<InvalidArgumentsMethodResponse>()),
+      );
+    });
+
+    test('should handle response with multiple errors and find the correct one', () {
+      // Arrange
+      final targetError = SetError(
+        ErrorMethodResponse.invalidArguments,
+        description: 'Target error',
+      );
+      final otherError = SetError(
+        ErrorMethodResponse.serverFail,
+        description: 'Other error',
+      );
+      final response = SetLabelResponse(
+        accountId,
+        notCreated: {
+          Id('other-1'): otherError,
+          requestId: targetError,
+          Id('other-2'): otherError,
+        },
+      );
+
+      // Act & Assert
+      expect(
+        () => testHandler.parseErrorForSetResponse(response, requestId),
+        throwsA(
+          isA<InvalidArgumentsMethodResponse>().having(
+            (e) => e.description,
+            'description',
+            'Target error',
+          ),
+        ),
+      );
+    });
+
+    test('should handle null SetResponse', () {
+      // Act & Assert
+      expect(
+        () => testHandler.parseErrorForSetResponse(null, requestId),
+        throwsA(isA<UnknownMethodResponse>()),
+      );
+    });
+
+    test('should handle SetError with notFound type', () {
+      // Arrange
+      final setError = SetError(SetError.notFound);
+      final response = SetLabelResponse(
+        accountId,
+        notCreated: {requestId: setError},
+      );
+
+      // Act & Assert
+      expect(
+        () => testHandler.parseErrorForSetResponse(response, requestId),
+        throwsA(isA<UnknownMethodResponse>()),
+      );
+    });
+
+    test('should handle SetError with forbidden type', () {
+      // Arrange
+      final setError = SetError(SetError.forbidden);
+      final response = SetLabelResponse(
+        accountId,
+        notCreated: {requestId: setError},
+      );
+
+      // Act & Assert
+      expect(
+        () => testHandler.parseErrorForSetResponse(response, requestId),
+        throwsA(isA<UnknownMethodResponse>()),
+      );
+    });
+
+    test('should handle response when error in notDestroyed only', () {
+      // Arrange
+      final setError = SetError(ErrorMethodResponse.invalidArguments);
+      final response = SetLabelResponse(
+        accountId,
+        notDestroyed: {requestId: setError},
+      );
+
+      // Act & Assert
+      expect(
+        () => testHandler.parseErrorForSetResponse(response, requestId),
+        throwsA(isA<InvalidArgumentsMethodResponse>()),
+      );
+    });
+
+    test('should handle empty response correctly', () {
+      // Arrange
+      final response = SetLabelResponse(accountId);
+
+      // Act & Assert
+      expect(
+        () => testHandler.parseErrorForSetResponse(response, requestId),
+        throwsA(isA<UnknownMethodResponse>()),
+      );
+    });
+
+    test('should preserve error descriptions correctly', () {
+      // Arrange
+      const testDescription = 'Duplicate label name exists';
+      final setError = SetError(
+        ErrorMethodResponse.invalidArguments,
+        description: testDescription,
+      );
+      final response = SetLabelResponse(
+        accountId,
+        notCreated: {requestId: setError},
+      );
+
+      // Act
+      try {
+        testHandler.parseErrorForSetResponse(response, requestId);
+        fail('Should have thrown exception');
+      } catch (e) {
+        // Assert
+        expect(e, isA<InvalidArgumentsMethodResponse>());
+        expect((e as InvalidArgumentsMethodResponse).description, testDescription);
+      }
+    });
+  });
+}