add article

internal/domains/article/entities/errors.go

@@ -0,0 +1,21 @@
+package entities
+
+// ValidationError 验证错误
+type ValidationError struct {
+	Message string
+}
+
+func (e *ValidationError) Error() string {
+	return e.Message
+}
+
+// NewValidationError 创建验证错误
+func NewValidationError(message string) *ValidationError {
+	return &ValidationError{Message: message}
+}
+
+// IsValidationError 判断是否为验证错误
+func IsValidationError(err error) bool {
+	_, ok := err.(*ValidationError)
+	return ok
+}