Add package reference to .NET Framework ref assemblies for x-plat work

Workaround dotnet/sdk#335

Author: busgaidw2

Directory.Build.props

@@ -33,4 +33,9 @@
     <BaseOutputPath>$(MSBuildThisFileDirectory).build\bin\$(MSBuildProjectName)\</BaseOutputPath>
   </PropertyGroup>
 
+  <ItemGroup>
+    <!-- For x-plat develpment. Workaround for https://github.com/dotnet/sdk/issues/335 -->
+    <PackageReference Include="Microsoft.NETFramework.ReferenceAssemblies" Version="1.0.0-alpha-004" PrivateAssets="all" />
+  </ItemGroup>
+
 </Project>

NuGet.config

@@ -3,5 +3,6 @@
   <packageSources>
     <clear />
     <add key="NuGet" value="https://api.nuget.org/v3/index.json" />
+    <add key="roslyntools" value="https://dotnet.myget.org/F/roslyn-tools/api/v3/index.json" />
   </packageSources>
-</configuration>
+</configuration>

build.ps1

@@ -64,8 +64,15 @@ Remove-Item -Recurse $artifacts -ErrorAction Ignore
 
 exec dotnet build --configuration $Configuration '-warnaserror:CS1591' @MSBuildArgs
 exec dotnet pack --no-restore --no-build --configuration $Configuration -o $artifacts @MSBuildArgs
+
+[string[]] $testArgs=@()
+if (-not $IsCoreCLR -or -not $IsWindows) {
+    $testArgs += '--framework','netcoreapp2.1'
+}
+
 exec dotnet test --no-restore --no-build --configuration $Configuration '-clp:Summary' `
     "$PSScriptRoot/test/CommandLineUtils.Tests/McMaster.Extensions.CommandLineUtils.Tests.csproj" `
+    @testArgs `
     @MSBuildArgs
 
 write-host -f magenta 'Done'

src/CommandLineUtils/McMaster.Extensions.CommandLineUtils.csproj

@@ -1,8 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
-
+  
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netstandard1.6</TargetFrameworks>
-    <TargetFrameworks Condition="$([MSBuild]::IsOSPlatform(Windows))">$(TargetFrameworks);net45</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;netstandard1.6;net45</TargetFrameworks>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <IsPackable>true</IsPackable>
     <Description>Command-line parsing API. A community-maintained fork of Microsoft.Extensions.CommandLineUtils, plus extras.

test/CommandLineUtils.Tests/McMaster.Extensions.CommandLineUtils.Tests.csproj

@@ -1,8 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.1</TargetFrameworks>
-    <TargetFrameworks Condition="$([MSBuild]::IsOSPlatform(Windows))">$(TargetFrameworks);net461</TargetFrameworks>
+    <TargetFrameworks>netcoreapp2.1;net461</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup>