Building VS 2017 MSBuild csproj Projects with Mono on Linux

There are two options here, as far as I'm aware:

• Use the FrameworkPathOverride environment variable as described in this issue to point to them.

• Restrict your Travis build to only build against .NET Core. This is significantly simpler in my experience.

Here's the Noda Time .travis.yml file I'll be using for Noda Time when I can migrate - it's preliminary to say the least, but it does build...

language: csharp
mono: none
dotnet: 1.0.1
dist: trusty

script:
  - dotnet restore src/NodaTime
  - dotnet restore src/NodaTime.Test
  - dotnet restore src/NodaTime.Serialization.Test
  - dotnet build src/NodaTime -f netstandard1.3
  - dotnet build src/NodaTime.Test -f netcoreapp1.0
  - dotnet build src/NodaTime.Serialization.Test -f netcoreapp1.0
  - dotnet run -p src/NodaTime.Test/*.csproj -f netcoreapp1.0 -- --where=cat!=Slow
  - dotnet run -p src/NodaTime.Serialization.Test/*.csproj -f netcoreapp1.0

A few notes on this:

• Unlike earlier SDKs, we now need to restore each project separately - no big "dotnet restore at the top level" :(
• I was surprised when this didn't run on dist: xenial, but it didn't. (It claims the environment doesn't support .NET Core.) My guess is this will change.
• We're using NUnit, and at the moment the only way of testing in the new SDK is to use NUnitLite, hence dotnet run to run tests
• I'm slightly surprised I can't just specify the directory name for dotnet run (as per dotnet restore and dotnet build) but that seems to be the way of things. I'll hunt down a bug report...

In either case, I'd recommend also having a Windows-based CI build to check that everything builds and works on Windows (ideally testing each framework you support).