test.proj

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="4.0"
         DefaultTargets="Test"
         xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  
  <ItemGroup>
    <XunitRunnerMSBuild Include="$(MSBuildThisFileDirectory)packages\xunit.runner.msbuild*\build\*\xunit.runner.msbuild.dll" />
	<TestAssemblies Include="$(MSBuildThisFileDirectory)\test\**\bin\*\*Tests.dll" />
  </ItemGroup>
  
  <UsingTask
    AssemblyFile="@(XunitRunnerMSBuild)"
    TaskName="Xunit.Runner.MSBuild.xunit" 
	Condition="Exists('@(XunitRunnerMSBuild)')" />

  <Target Name="Test">
	<Error Condition="!Exists('@(XunitRunnerMSBuild)')"
		   Text="The xUnit Runner tools nuget package is not installed. Please run build.cmd from the root of the repo at least once to get the tools installed." />
	<Error Condition="'@(TestAssemblies)' == ''"
		   Text="No test binaries available for running. Please run build.cmd from the root of the repo at least once to build the test libraries." />
    <xunit Assemblies="@(TestAssemblies)" 
		   Verbose="false" />
  </Target>

</Project>