found conflicts between different versions .Net Core 2.2 inside test project

warning MSB3277: Found conflicts between different versions of “Microsoft.Extensions.Options” that could not be resolved.
warning MSB3277: Found conflicts between different versions of “Microsoft.Extensions.Configuration.Abstractions” that could not be resolved.
warning MSB3277: Found conflicts between different versions of “Microsoft.AspNetCore.Hosting.Abstractions” that could not be resolved.
warning MSB3277: Found conflicts between different versions of “Microsoft.Extensions.DependencyInjection.Abstractions” that could not be resolved.
warning MSB3277: Found conflicts between different versions of “Microsoft.AspNetCore.Http.Abstractions” that could not be resolved.
warning MSB3277: Found conflicts between different versions of “Microsoft.AspNetCore.Http.Features” that could not be resolved.

A quick fix is to add the following package in your project that throws the warnings:

<PackageReference Include="Microsoft.AspNetCore.App" />

Rebuild your project and boom! All the warnings are gone!

Better news: starting with .NET Core 3.0, the web reference will flow transitively and you can reference a web project from a test project without any other steps. So I am closing this. The design of 2.x cannot be changed, but we specifically designed things in 3.0 to have transitive FrameworkReferences, and this was a motivating scenario for that.

Happy coding!