diff --git a/Activout.RestClient.Test/Activout.RestClient.Test.csproj b/Activout.RestClient.Test/Activout.RestClient.Test.csproj
index e590e91..1651d3e 100644
--- a/Activout.RestClient.Test/Activout.RestClient.Test.csproj
+++ b/Activout.RestClient.Test/Activout.RestClient.Test.csproj
@@ -3,6 +3,7 @@
     <IsPackable>false</IsPackable>
     <TargetFramework>net8.0</TargetFramework>
     <LangVersion>default</LangVersion>
+    <Nullable>enable</Nullable>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
     <WarningsNotAsErrors>CS0618;CS0619</WarningsNotAsErrors>
   </PropertyGroup>
diff --git a/Activout.RestClient.Test/BodyArgumentFormPostTest.cs b/Activout.RestClient.Test/BodyArgumentFormPostTest.cs
index e32f88e..deac406 100644
--- a/Activout.RestClient.Test/BodyArgumentFormPostTest.cs
+++ b/Activout.RestClient.Test/BodyArgumentFormPostTest.cs
@@ -1,3 +1,4 @@
+#nullable disable
 using System;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
diff --git a/Activout.RestClient.Test/CancellationTokenBodyTest.cs b/Activout.RestClient.Test/CancellationTokenBodyTest.cs
index 7aa152a..79bac79 100644
--- a/Activout.RestClient.Test/CancellationTokenBodyTest.cs
+++ b/Activout.RestClient.Test/CancellationTokenBodyTest.cs
@@ -1,3 +1,4 @@
+#nullable disable
 using System;
 using System.Net;
 using System.Net.Http;
diff --git a/Activout.RestClient.Test/DictionaryParameterTests.cs b/Activout.RestClient.Test/DictionaryParameterTests.cs
index 6edf1bb..e91eaf4 100644
--- a/Activout.RestClient.Test/DictionaryParameterTests.cs
+++ b/Activout.RestClient.Test/DictionaryParameterTests.cs
@@ -1,3 +1,4 @@
+#nullable disable
 using System;
 using System.Collections;
 using System.Collections.Generic;
diff --git a/Activout.RestClient.Test/ErrorResponseTextPlainTest.cs b/Activout.RestClient.Test/ErrorResponseTextPlainTest.cs
index 413bf42..3858f16 100644
--- a/Activout.RestClient.Test/ErrorResponseTextPlainTest.cs
+++ b/Activout.RestClient.Test/ErrorResponseTextPlainTest.cs
@@ -1,3 +1,4 @@
+#nullable disable
 using System.Net;
 using System.Net.Http;
 using System.Threading.Tasks;
diff --git a/Activout.RestClient.Test/HttpRequestMessageCollector.cs b/Activout.RestClient.Test/HttpRequestMessageCollector.cs
index 36b6577..eb0748a 100644
--- a/Activout.RestClient.Test/HttpRequestMessageCollector.cs
+++ b/Activout.RestClient.Test/HttpRequestMessageCollector.cs
@@ -1,3 +1,4 @@
+#nullable disable
 using System.Net.Http;
 
 namespace Activout.RestClient.Test
diff --git a/Activout.RestClient.Test/HttpResponseMessageTest.cs b/Activout.RestClient.Test/HttpResponseMessageTest.cs
index 7c596af..a97beae 100644
--- a/Activout.RestClient.Test/HttpResponseMessageTest.cs
+++ b/Activout.RestClient.Test/HttpResponseMessageTest.cs
@@ -1,3 +1,4 @@
+#nullable disable
 using System;
 using System.Net;
 using System.Net.Http;
diff --git a/Activout.RestClient.Test/HttpStatusCodeTest.cs b/Activout.RestClient.Test/HttpStatusCodeTest.cs
index 9a7dcc1..e9f2f9c 100644
--- a/Activout.RestClient.Test/HttpStatusCodeTest.cs
+++ b/Activout.RestClient.Test/HttpStatusCodeTest.cs
@@ -1,3 +1,4 @@
+#nullable disable
 using System;
 using System.Net;
 using System.Net.Http;
diff --git a/Activout.RestClient.Test/LoggerFactoryHelpers.cs b/Activout.RestClient.Test/LoggerFactoryHelpers.cs
index 1b4e8cc..a7840ce 100644
--- a/Activout.RestClient.Test/LoggerFactoryHelpers.cs
+++ b/Activout.RestClient.Test/LoggerFactoryHelpers.cs
@@ -1,3 +1,4 @@
+#nullable disable
 using Microsoft.Extensions.Logging;
 using Xunit.Abstractions;
 
diff --git a/Activout.RestClient.Test/MediaTypeTests.cs b/Activout.RestClient.Test/MediaTypeTests.cs
index 9e37e35..676ae32 100644
--- a/Activout.RestClient.Test/MediaTypeTests.cs
+++ b/Activout.RestClient.Test/MediaTypeTests.cs
@@ -1,3 +1,4 @@
+#nullable disable
 using System;
 using Xunit;
 
diff --git a/Activout.RestClient.Test/MovieReviews/ErrorResponse.cs b/Activout.RestClient.Test/MovieReviews/ErrorResponse.cs
index 6fb09f3..5046ae6 100644
--- a/Activout.RestClient.Test/MovieReviews/ErrorResponse.cs
+++ b/Activout.RestClient.Test/MovieReviews/ErrorResponse.cs
@@ -1,3 +1,4 @@
+#nullable disable
 using System.Collections.Generic;
 
 namespace Activout.RestClient.Test.MovieReviews;
diff --git a/Activout.RestClient.Test/MovieReviews/IMovieReviewService.cs b/Activout.RestClient.Test/MovieReviews/IMovieReviewService.cs
index a2a672a..1242ceb 100644
--- a/Activout.RestClient.Test/MovieReviews/IMovieReviewService.cs
+++ b/Activout.RestClient.Test/MovieReviews/IMovieReviewService.cs
@@ -1,3 +1,4 @@
+#nullable disable
 using System.Diagnostics.CodeAnalysis;
 using System.Net.Http;
 using System.Threading;
diff --git a/Activout.RestClient.Test/MultipartFormDataContentTest.cs b/Activout.RestClient.Test/MultipartFormDataContentTest.cs
index 1bd2519..e5a98a6 100644
--- a/Activout.RestClient.Test/MultipartFormDataContentTest.cs
+++ b/Activout.RestClient.Test/MultipartFormDataContentTest.cs
@@ -1,3 +1,4 @@
+#nullable disable
 using System;
 using System.Linq;
 using System.Net;
diff --git a/Activout.RestClient.Test/NonJsonRestClientTests.cs b/Activout.RestClient.Test/NonJsonRestClientTests.cs
index f7916f7..7332055 100644
--- a/Activout.RestClient.Test/NonJsonRestClientTests.cs
+++ b/Activout.RestClient.Test/NonJsonRestClientTests.cs
@@ -1,3 +1,4 @@
+#nullable disable
 using System;
 using System.Linq;
 using System.Net;
diff --git a/Activout.RestClient.Test/NullParameterTests.cs b/Activout.RestClient.Test/NullParameterTests.cs
index 2606c2b..2880e0f 100644
--- a/Activout.RestClient.Test/NullParameterTests.cs
+++ b/Activout.RestClient.Test/NullParameterTests.cs
@@ -1,3 +1,4 @@
+#nullable disable
 using System.Collections.Generic;
 using System.Net.Http;
 using System.Threading.Tasks;
diff --git a/Activout.RestClient.Test/ParamConverterTests.cs b/Activout.RestClient.Test/ParamConverterTests.cs
index 8ff5a86..0e9a660 100644
--- a/Activout.RestClient.Test/ParamConverterTests.cs
+++ b/Activout.RestClient.Test/ParamConverterTests.cs
@@ -1,3 +1,4 @@
+#nullable disable
 using System;
 using System.Reflection;
 using Activout.RestClient.ParamConverter;
diff --git a/Activout.RestClient.Test/RestClientExceptionTest.cs b/Activout.RestClient.Test/RestClientExceptionTest.cs
index 2d530b7..7221134 100644
--- a/Activout.RestClient.Test/RestClientExceptionTest.cs
+++ b/Activout.RestClient.Test/RestClientExceptionTest.cs
@@ -1,4 +1,5 @@
-using System;
+#nullable disable
+using System;
 using System.IO;
 using System.Net;
 using System.Runtime.Serialization.Formatters.Binary;