Repro for a error in dotnet test I ran into with .NET 5 RC1.

This repository consits of a simple class library and a unit test project that depends on it.

Under certain conditions, dotnet test fails because the project cannot be built.

What works:

• dotnet build Repro.sln
• dotnet test Repro.sln --no-build
• dotnet test Repro.Test\Repro.Test.csproj

What doesn't work:

• dotnet test Repro.sln

Note: Problem only occurs when the main project uses multi-targeting.

When changing <TargetFrameworks>netcoreapp3.1;net5.0</TargetFrameworks> in Repro.csproj to <TargetFramework>net5.0</TargetFramework>, dotnet test seems to work fine.