JsonArrayValidator.cs

using System.Collections.Generic;
using System.Linq;
using Microsoft.OpenApi.Models;
using Newtonsoft.Json.Linq;

namespace Swashbuckle.AspNetCore.ApiTesting
{
    public class JsonArrayValidator(IJsonValidator jsonValidator) : IJsonValidator
    {
        private readonly IJsonValidator _jsonValidator = jsonValidator;

        public bool CanValidate(OpenApiSchema schema) => schema.Type == "array";

        public bool Validate(
            OpenApiSchema schema,
            OpenApiDocument openApiDocument,
            JToken instance,
            out IEnumerable<string> errorMessages)
        {
            if (instance.Type != JTokenType.Array)
            {
                errorMessages = [$"Path: {instance.Path}. Instance is not of type 'array'"];
                return false;
            }

            var arrayInstance = (JArray)instance;
            var errorMessagesList = new List<string>();

            // items
            if (schema.Items != null)
            {
                foreach (var itemInstance in arrayInstance)
                {
                    if (!_jsonValidator.Validate(schema.Items, openApiDocument, itemInstance, out IEnumerable<string> itemErrorMessages))
                    {
                        errorMessagesList.AddRange(itemErrorMessages);
                    }
                }
            }

            // maxItems
            if (schema.MaxItems.HasValue && (arrayInstance.Count > schema.MaxItems.Value))
            {
                errorMessagesList.Add($"Path: {instance.Path}. Array size is greater than maxItems");
            }

            // minItems
            if (schema.MinItems.HasValue && (arrayInstance.Count < schema.MinItems.Value))
            {
                errorMessagesList.Add($"Path: {instance.Path}. Array size is less than minItems");
            }

            // uniqueItems
            if (schema.UniqueItems.HasValue && (arrayInstance.Count != arrayInstance.Distinct().Count()))
            {
                errorMessagesList.Add($"Path: {instance.Path}. Array does not contain uniqueItems");
            }

            errorMessages = errorMessagesList;
            return !errorMessages.Any();
        }
    }
}