CoverageTargets does not work with local package as Testable Target Reference

I defined the package:

packages:
  MyPackage:
    path: ../MyPackage

And used it in:

    test:
      config: Release_Debug
      language: en
      region: US
      gatherCoverageData: true
      coverageTargets:
        - MyApp
        - MyPackage/MyPackage

Xcodegen complained that Scheme "Release (Debug)" has invalid project reference "MyPackage", also I don't know how to define the target as local package vs project reference, from here the local package and project reference are using the same syntax

Start with the Testable Target Reference section linked in the issue and reproduce the shown package, test configuration, and XcodeGen error. Trace how CoverageTargets resolves a local package versus a project reference; done means the configuration generates a valid scheme with MyPackage/MyPackage as a coverage target.