diff --git a/Directory.Build.targets b/Directory.Build.targets
index 233f9c6d..b651a1a4 100644
--- a/Directory.Build.targets
+++ b/Directory.Build.targets
@@ -10,6 +10,10 @@
     <AssemblyOriginatorKeyFile>$(MSBuildThisFileDirectory)graphql.snk</AssemblyOriginatorKeyFile>
   </PropertyGroup>
 
+  <PropertyGroup Condition="'$(TargetFramework)' == 'netcoreapp2.1'">
+    <RuntimeFrameworkVersion>2.1.30</RuntimeFrameworkVersion>
+  </PropertyGroup>
+
   <ItemGroup Condition="'$(IsTestProject)' != 'true'">
     <InternalsVisibleTo Condition="'$(SignAssembly)' == 'true'" Include="$(AssemblyName).Tests, $(_FriendAssembliesPublicKey)"/>
     <InternalsVisibleTo Condition="'$(SignAssembly)' != 'true'" Include="$(AssemblyName).Tests"/>
diff --git a/tests/Samples.Tests/Samples.Tests.csproj b/tests/Samples.Tests/Samples.Tests.csproj
index 061fadd0..1df87c6b 100644
--- a/tests/Samples.Tests/Samples.Tests.csproj
+++ b/tests/Samples.Tests/Samples.Tests.csproj
@@ -17,4 +17,8 @@
     <PackageReference Include="GraphQL.SystemTextJson" Version="$(GraphQLVersion)" />
   </ItemGroup>
 
+  <ItemGroup>
+    <Using Include="System.Net.Http"/>
+  </ItemGroup>
+
 </Project>
diff --git a/tests/Transports.AspNetCore.Tests/Transports.AspNetCore.Tests.csproj b/tests/Transports.AspNetCore.Tests/Transports.AspNetCore.Tests.csproj
index 82b5927a..e1af857b 100644
--- a/tests/Transports.AspNetCore.Tests/Transports.AspNetCore.Tests.csproj
+++ b/tests/Transports.AspNetCore.Tests/Transports.AspNetCore.Tests.csproj
@@ -43,6 +43,7 @@
     <Using Include="Moq" />
     <Using Include="Moq.Protected" />
     <Using Include="Shouldly" />
+    <Using Include="System.Net.Http"/>
     <Using Include="System.Text" />
     <Using Include="System.Threading" />
     <Using Include="System.Threading.Tasks" />