NuGet for test projects

[vslee]

Is your feature request related to a problem? Please describe.

The test projects contain useful things for consumers, such as JoinableTaskTestBase.SimulateUIThread().

Describe the solution you'd like

NuGets which contain the test projects. For example:
https://www.nuget.org/packages/Microsoft.EntityFrameworkCore.Relational.Specification.Tests/
https://www.nuget.org/packages/Microsoft.Extensions.DependencyInjection.Specification.Tests/
https://www.nuget.org/packages/Microsoft.AspNetCore.Identity.Specification.Tests/

Describe alternatives you've considered

Currently, I fetch the vs-threading source every once in a while and add a project reference in Visual Studio. But a NuGet would be a cleaner solution.

[AArnott]

You don't actually want the unit test themselves, but rather you're looking for us to share the helper methods we use within the tests so that you can use them in your tests as well, I believe.

That's a fine idea. You mention SimulateUIThread as one example. Are there others?

[vslee]

I am only a light user, so SimulateUIThread is the only one I know of. However, if you only include a few select helper methods in the NuGet, then ppl who are looking for others may get confused as to why it's not working. You're right that the unit tests themselves are not needed in the NuGet, but since they will only be referenced by other test projects, a little bit of bloat wouldn't hurt. Thus, it may be easier to just include everything.

[AArnott]

We're not going to ship our unit tests themselves in nuget packages. I don't know how offering a new test utility package with some helper methods would confuse people as to why it's not working unless they were previously reaching directly into our test projects, which isn't something we support and I hope is quite rare.

But as it is, this is a low priority relative to our many other deliverables, so I don't think we'll be taking either direction right away.