The assembly for this test is not found

I opened an existing DotNet (Core 3.1 and netstandard2.1 projects) with Rider. It builds properly but it does not find any xUnit tests. None, and there should be around 400 in different projects within the solution.

The error I get is:

If I try to execute a test directly by clicking Run button on the source file I can see the following error:

The assembly for this test is not found (D:\src\sg\whatever\tests\Foo.Modules\Foo.Bar.Tests\bin\Debug\netcoreapp3.1\bin\Foo.Bar.Tests.dll)

Indeed, the Tests.dll are not in that path. They are at D:\src\sg\whatever\tests\Foo.Modules\Foo.Bar.Tests\bin\Debug\netcoreapp3.1\Foo.Bar.Tests.dll (without the last bin folder)

I have tried to run the tests in Visual Studio test explorer and they are all found and runnable.

However when I try with Visual Studio + Resharper I have the same issue, no tests found at all, so I suspect it must be something related to some configuration that resharper/Raider uses for finding test assemblies.

Why is Rider or ReSharper not finding any xUnit test at all? Why is looking at the wrong path for the test dll? Where is that being configured or how is this supposed to work?

Thanks!