Several adjustments needed

Kontent.Ai.Management.Tests/CodeSamples/Readme.cs

@@ -12,6 +12,7 @@
 using System;
 using System.IO;
 using System.Linq;
+using System.Net.Http;
 using System.Text;
 using Xunit;
 
@@ -73,7 +74,7 @@ public void CreateManagementClient()
         {
             EnvironmentId = "cbbe2d5c-17c6-0128-be26-e997ba7c1619",
             ApiKey = "ew0...1eo"
-        });
+        }, new HttpClient());
     }
 
     [Fact]

Kontent.Ai.Management/ManagementClient.cs

@@ -1,14 +1,14 @@
-using Kontent.Ai.Management.Configuration;
+using System;
+using System.Collections.Generic;
+using System.Net.Http;
+using System.Threading.Tasks;
+using Kontent.Ai.Management.Configuration;
 using Kontent.Ai.Management.Models.Shared;
 using Kontent.Ai.Management.Modules.ActionInvoker;
 using Kontent.Ai.Management.Modules.HttpClient;
 using Kontent.Ai.Management.Modules.ModelBuilders;
 using Kontent.Ai.Management.Modules.ResiliencePolicy;
 using Kontent.Ai.Management.Modules.UrlBuilder;
-using System;
-using System.Collections.Generic;
-using System.Net.Http;
-using System.Threading.Tasks;
 
 namespace Kontent.Ai.Management;
 
@@ -27,7 +27,8 @@ public sealed partial class ManagementClient : IManagementClient
     /// Initializes a new instance of the <see cref="ManagementClient"/> class for managing content of the specified environment.
     /// </summary>
     /// <param name="ManagementOptions">The settings of the Kontent.ai environment.</param>
-    public ManagementClient(ManagementOptions ManagementOptions)
+    /// <param name="httpClient"></param>
+    public ManagementClient(ManagementOptions ManagementOptions, System.Net.Http.HttpClient httpClient)
     {
         ArgumentNullException.ThrowIfNull(ManagementOptions);
 
@@ -49,7 +50,7 @@ public ManagementClient(ManagementOptions ManagementOptions)
 
         _urlBuilder = new EndpointUrlBuilder(ManagementOptions);
         _actionInvoker = new ActionInvoker(
-            new ManagementHttpClient(new DefaultResiliencePolicyProvider(ManagementOptions.MaxRetryAttempts), ManagementOptions.EnableResilienceLogic),
+            new ManagementHttpClient(new Modules.HttpClient.HttpClient(httpClient), new DefaultResiliencePolicyProvider(ManagementOptions.MaxRetryAttempts), ManagementOptions.EnableResilienceLogic),
             new MessageCreator(ManagementOptions.ApiKey));
         _modelProvider = ManagementOptions.ModelProvider ?? new ModelProvider();
     }

Kontent.Ai.Management/Models/Items/ContentItemCreateModel.cs

@@ -1,12 +1,12 @@
-using Kontent.Ai.Management.Models.Shared;
+using Kontent.Ai.Management.Models.Shared;
 using Newtonsoft.Json;
 
 namespace Kontent.Ai.Management.Models.Items;
 
 /// <summary>
 /// Represents the content item create model.
 /// </summary>
-public sealed class ContentItemCreateModel
+public class ContentItemCreateModel
 {
     /// <summary>
     /// Gets or sets the name of the content item.

Kontent.Ai.Management/Models/Shared/AssetWithRenditionsReference.cs

@@ -1,16 +1,16 @@
-using Kontent.Ai.Management.Modules.ActionInvoker;
-using Newtonsoft.Json;
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Kontent.Ai.Management.Modules.ActionInvoker;
+using Newtonsoft.Json;
 
 namespace Kontent.Ai.Management.Models.Shared;
 
 /// <summary>
 /// Represents identifier of asset with renditions.
 /// </summary>
 [JsonConverter(typeof(AssetWithRenditionsReferenceConverter))]
-public sealed class AssetWithRenditionsReference
+public class AssetWithRenditionsReference
 {
     private readonly IList<Reference> _renditions;
 
@@ -60,4 +60,4 @@ public AssetWithRenditionsReference(Reference assetReference, IEnumerable<Refere
         _assetReference = assetReference;
         _renditions = renditionReferences?.ToList() ?? new List<Reference>();
     }
-}
+}

Kontent.Ai.Management/Models/Types/Elements/ElementMetadataBase.cs

@@ -1,7 +1,7 @@
-using Kontent.Ai.Management.Models.Shared;
+using System;
+using Kontent.Ai.Management.Models.Shared;
 using Kontent.Ai.Management.Modules.ActionInvoker;
 using Newtonsoft.Json;
-using System;
 
 namespace Kontent.Ai.Management.Models.Types.Elements;
 
@@ -27,7 +27,7 @@ public abstract class ElementMetadataBase
     /// Gets or sets the element's internal ID.
     /// </summary>
     [JsonProperty("id")]
-    public Guid Id { get; private set; }
+    public Guid Id { get; set; }
 
     /// <summary>
     /// Gets or sets the element's codename.

Kontent.Ai.Management/Modules/ActionInvoker/ActionInvoker.cs

@@ -1,13 +1,13 @@
-using Kontent.Ai.Management.Modules.HttpClient;
-using Newtonsoft.Json;
-using Newtonsoft.Json.Converters;
 using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Net.Http;
 using System.Net.Http.Headers;
 using System.Text;
 using System.Threading.Tasks;
+using Kontent.Ai.Management.Modules.HttpClient;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Converters;
 
 namespace Kontent.Ai.Management.Modules.ActionInvoker;
 
@@ -19,12 +19,12 @@ internal class ActionInvoker : IActionInvoker
     private readonly JsonSerializerSettings _serializeSettings = new()
     {
         NullValueHandling = NullValueHandling.Ignore,
-        Converters = new List<JsonConverter> { new DecimalObjectConverter(), new StringEnumConverter() }
+        Converters = [new DecimalObjectConverter(), new StringEnumConverter()]
     };
 
     private readonly JsonSerializerSettings _deserializeSettings = new()
     {
-        Converters = new List<JsonConverter> { new DynamicObjectJsonConverter() }
+        Converters = [new DynamicObjectJsonConverter()]
     };
 
 
@@ -60,6 +60,10 @@ public async Task<TResponse> InvokeMethodAsync<TPayload, TResponse>(string endpo
     public async Task<TResponse> InvokeReadOnlyMethodAsync<TResponse>(string endpointUrl, HttpMethod method, Dictionary<string, string> headers = null)
     {
         var response = await _cmHttpClient.SendAsync(_messageCreator, endpointUrl, method, null, headers);
+        if (response == null)
+        {
+            return default;
+        }
 
         return await ReadResultAsync<TResponse>(response);
     }

Kontent.Ai.Management/Modules/HttpClient/HttpClient.cs

@@ -5,6 +5,15 @@ namespace Kontent.Ai.Management.Modules.HttpClient;
 
 internal class HttpClient : IHttpClient
 {
+    public HttpClient()
+    {
+
+    }
+    public HttpClient(System.Net.Http.HttpClient httpClient)
+    {
+        _baseClient = httpClient;
+    }
+
     private readonly System.Net.Http.HttpClient _baseClient = new();
 
     public async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request) => await _baseClient.SendAsync(request);

Kontent.Ai.Management/Modules/HttpClient/ManagementHttpClient.cs

@@ -73,6 +73,11 @@ public async Task<HttpResponseMessage> SendAsync(
             return response;
         }
 
+        if (response.StatusCode == System.Net.HttpStatusCode.NotFound)
+        {
+            return null;
+        }
+
         var responseContent = response.Content;
 
         throw responseContent != null ?