Is it possible to have multiple Play Mode test assemblies?

I have an empty Unity project using 2019.1.2f1.

I create a local package, add it as a reference to my empty project, and follow the following steps to create a play mode test assembly:
https://docs.unity3d.com/Packages/c...1.1/manual/workflow-create-playmode-test.html

I now create a second local package and add it as a reference. I cannot follow the steps in the link above, because the Test Runner window no longer has the 'Create PlayMode Test Assembly' button, so I attempt to create it manually via 'Create -> Testing -> Tests Assembly Folder' and 'C# Test Script.'

If I open the test runner, it doesn't show the second test assembly, only the first. The generated Visual Studio solution also doesn't contain a project for the second test assembly.

I don't see any errors or warnings in the console, but it seems like Unity is completely ignoring the second project's test assembly; it's not even attempting to import the test script. However, if I uncheck 'Test Assemblies' in my asmdef, it does compile the assembly.

Is it not possible to have multiple Play Mode test assemblies, or am I doing something wrong?

 

Disregard, this was a dumb problem: the second package didn't get included as testable in the package manifest, for some reason. It might be useful to have some sort of diagnostic for this, though