diff --git a/.github/workflows/test-coverage.yaml b/.github/workflows/test-coverage.yaml
index 6ba4cd79..7f8205d4 100644
--- a/.github/workflows/test-coverage.yaml
+++ b/.github/workflows/test-coverage.yaml
@@ -21,7 +21,7 @@ jobs:
         uses: DeterminateSystems/nix-installer-action@main
 
       - name: Test coverage
-        run: nix-shell -p R rPackages.covr rPackages.codetools --run "Rscript -e 'covr::codecov(quiet = FALSE, clean = FALSE, install_path = file.path(Sys.getenv(\"RUNNER_TEMP\"), \"package\"))' "
+        run: nix-shell -p R rPackages.covr rPackages.codetools r.Packages.testthat --run "Rscript -e 'covr::codecov(quiet = FALSE, clean = FALSE, install_path = file.path(Sys.getenv(\"RUNNER_TEMP\"), \"package\"))' "
 
       - name: Show testthat output
         if: always()