FIx tests

Author: akoeplinger

.nuget/packages.config

@@ -3,4 +3,5 @@
   <package id="Microsoft.Web.SkipStrongNames" version="1.0.0" />
   <package id="Microsoft.Web.StyleCop" version="1.0.0" />
   <package id="StyleCop" version="5.0.0" />
+  <package id="xunit.runner.msbuild" version="2.4.2" targetFramework="net452" />
 </packages>

eng/templates/default-build.yml

@@ -46,6 +46,11 @@ jobs:
     inputs:
       packageType: runtime
       version: '2.1.x'
+  - task: UseDotNet@2
+    displayName: Get .NET 6.0 runtime
+    inputs:
+      packageType: runtime
+      version: '6.0.x'
 
   - script: .\build.cmd EnableSkipStrongNames
     displayName: Enable SkipStrongNames

tools/WebStack.testing.targets

@@ -3,6 +3,7 @@
     This is a separate MSBuild file so that we can survive upgrades of the xunit NuGet package
     and also still work with NuGet Package Restore.
   -->
+  <Import Project="..\packages\xunit.runner.msbuild.2.4.2\**\xunit.runner.msbuild.props"/>
 
   <Target Name="TestAssembly" Returns="@(_ExitCodes)">
     <xunit Assemblies="$(TestAssembly)"