Change NuGet package to use None ItemGroup to copy files to output directory

[inthemedium]

Without this change, files from this nuget package will be included
automatically when the consuming project is packing.

Example error when packing a project:

C:\Program Files\dotnet\sdk\3.1.200\Sdks\NuGet.Build.Tasks.Pack\build\NuGet.Build.Tasks.Pack.targets(198,5):
warning NU5100: The assembly 'content\Microsoft.VisualStudio.TestPlatform.MSTest.TestAdapter.dll' is
not inside the 'lib' folder and hence it won't be added as a reference
when the package is installed into a project. Move it into the 'lib'
folder if it needs to be referenced.

Additionally, add the contents to an ItemGroup so they can be seperated later if needed.

[nohwnd]

Thanks for the PR, added it to 16.7.0. If you shared a bit more about why this is an issue, and how to replicate it, that would be great 🙂

[inthemedium]

Thanks for the PR, added it to 16.7.0. If you shared a bit more about why this is an issue, and how to replicate it, that would be great 🙂

Why it's an issue: any projects package referencing the MSTest.TestAdapter cannot be packed without non-trivial modifications to get rid of the pack warnings.

Here's a sample .csproj file that illustrates the issue:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp3.1</TargetFramework>
    <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="MSTest.TestAdapter" Version="2.1.0" />
  </ItemGroup>
</Project>

Output:

1>------ Build started: Project: ConsoleApp22, Configuration: Debug Any CPU ------
1>ConsoleApp22 -> C:\Users\...\source\repos\ConsoleApp22\ConsoleApp22\bin\Debug\netcoreapp3.1\ConsoleApp22.dll
1>Successfully created package 'C:\Users\...\source\repos\ConsoleApp22\ConsoleApp22\bin\Debug\ConsoleApp22.1.0.0.nupkg'.
1>C:\Program Files\dotnet\sdk\3.1.200\Sdks\NuGet.Build.Tasks.Pack\build\NuGet.Build.Tasks.Pack.targets(198,5): warning NU5100: The assembly 'content\Microsoft.VisualStudio.TestPlatform.MSTest.TestAdapter.dll' is not inside the 'lib' folder and hence it won't be added as a reference when the package is installed into a project. Move it into the 'lib' folder if it needs to be referenced.
1>C:\Program Files\dotnet\sdk\3.1.200\Sdks\NuGet.Build.Tasks.Pack\build\NuGet.Build.Tasks.Pack.targets(198,5): warning NU5100: The assembly 'contentFiles\any\netcoreapp3.1\Microsoft.VisualStudio.TestPlatform.MSTest.TestAdapter.dll' is not inside the 'lib' folder and hence it won't be added as a reference when the package is installed into a project. Move it into the 'lib' folder if it needs to be referenced.
1>C:\Program Files\dotnet\sdk\3.1.200\Sdks\NuGet.Build.Tasks.Pack\build\NuGet.Build.Tasks.Pack.targets(198,5): warning NU5100: The assembly 'content\Microsoft.VisualStudio.TestPlatform.MSTestAdapter.PlatformServices.Interface.dll' is not inside the 'lib' folder and hence it won't be added as a reference when the package is installed into a project. Move it into the 'lib' folder if it needs to be referenced.
1>C:\Program Files\dotnet\sdk\3.1.200\Sdks\NuGet.Build.Tasks.Pack\build\NuGet.Build.Tasks.Pack.targets(198,5): warning NU5100: The assembly 'contentFiles\any\netcoreapp3.1\Microsoft.VisualStudio.TestPlatform.MSTestAdapter.PlatformServices.Interface.dll' is not inside the 'lib' folder and hence it won't be added as a reference when the package is installed into a project. Move it into the 'lib' folder if it needs to be referenced.
1>C:\Program Files\dotnet\sdk\3.1.200\Sdks\NuGet.Build.Tasks.Pack\build\NuGet.Build.Tasks.Pack.targets(198,5): warning NU5100: The assembly 'content\Microsoft.VisualStudio.TestPlatform.MSTestAdapter.PlatformServices.dll' is not inside the 'lib' folder and hence it won't be added as a reference when the package is installed into a project. Move it into the 'lib' folder if it needs to be referenced.
1>C:\Program Files\dotnet\sdk\3.1.200\Sdks\NuGet.Build.Tasks.Pack\build\NuGet.Build.Tasks.Pack.targets(198,5): warning NU5100: The assembly 'contentFiles\any\netcoreapp3.1\Microsoft.VisualStudio.TestPlatform.MSTestAdapter.PlatformServices.dll' is not inside the 'lib' folder and hence it won't be added as a reference when the package is installed into a project. Move it into the 'lib' folder if it needs to be referenced.
1>Done building project "ConsoleApp22.csproj".
========== Build: 1 succeeded, 0 failed, 0 up-to-date, 0 skipped ==========

Expected output:

1>------ Build started: Project: ConsoleApp22, Configuration: Debug Any CPU ------
1>ConsoleApp22 -> C:\Users\...\source\repos\ConsoleApp22\ConsoleApp22\bin\Debug\netcoreapp3.1\ConsoleApp22.dll
1>Successfully created package 'C:\Users\...\source\repos\ConsoleApp22\ConsoleApp22\bin\Debug\ConsoleApp22.1.0.0.nupkg'.

[nohwnd]

Thanks, helps a lot :)