diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index 62ecb1b..33416da 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -34,6 +34,7 @@ jobs:
       - uses: julia-actions/julia-runtest@v1
         env:
           GROUP: ${{ matrix.group }}
+          GROUP_COVERAGE: true
       - uses: julia-actions/julia-processcoverage@v1
         with:
           directories: src,lib/AtomsIOPython/src
diff --git a/test/runtests.jl b/test/runtests.jl
index dd96264..3e9efb2 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -2,6 +2,7 @@ using Test
 using Pkg
 
 const GROUP = get(ENV, "GROUP", "Core")
+const GROUP_COVERAGE = !isempty(get(ENV, "GROUP_COVERAGE", ""))
 
 if GROUP == "Core"
     @testset "AtomsIO.jl" begin
@@ -13,5 +14,5 @@ if GROUP == "Core"
 else
     subpkg_path = joinpath(dirname(@__DIR__), "lib", GROUP)
     Pkg.develop(PackageSpec(path=subpkg_path))
-    Pkg.test(PackageSpec(name=GROUP, path=subpkg_path))
+    Pkg.test(PackageSpec(name=GROUP, path=subpkg_path), coverage=GROUP_COVERAGE)
 end