runtime: Debugging BCL test projects won't load test assembly

I am a potential contributor to the .NET BCL. I’ve encountered an issue trying to debug BCL tests from the VS test runner.

Description

I am unable to set breakpoints during debugging, unable to ‘break all’ (test will presumably continue running), unable to step through code as it will not break.

From the issues I’ve experienced, this problem shares similarities with issue #26732.

If a breakpoint is set beforehand, VS will inform me, hovering over it, that “No symbols have been loaded for this document”, even though this is the test that is being debugged from the VS test runner. I assume this is the cause of my issues. All managed assemblies are of the Debug configuration.

Edit: Attempting to find the tests assembly in the VS Modules window, I find it missing, along with the BCL library it should be testing. The test(s) never complete no matter how much time its given. Note: I’m debugging the tests for System.Text.RegularExpressions

Configuration

System Config: Windows, x64 VS 2019 Version 4.8.04084

Trying to debug tests found in the master branch of this repository, after using the build command line tool to build everything.

Other information

I’ve talked with people in the discord about this, people there suspect that its not loading the debug symbols because they aren’t being put in a spot that VS can find it. May or may not be fixable from the build script.

I admit that this may or may not be a completely isolated issue. I’m still not able to solve it myself.