try direct reference

Author: ChrisRackauckas

.ci/test.jl

@@ -3,12 +3,12 @@ import Pkg
 const GROUP = get(ENV, "GROUP", "All")
 
 function dev_subpkg(subpkg)
-    subpkg_path = joinpath(dirname(@__DIR__), "lib", subpkg)
+    subpkg_path = joinpath("lib", subpkg)
     Pkg.develop(Pkg.PackageSpec(path=subpkg_path))
 end
 
 function activate_subpkg_env(subpkg)
-    subpkg_path = joinpath(dirname(@__DIR__), "lib", subpkg)
+    subpkg_path = joinpath("lib", subpkg)
     Pkg.activate(subpkg_path)
     Pkg.develop(Pkg.PackageSpec(path=subpkg_path))
     Pkg.instantiate()