try this

Author: blink1073

.github/actions/test-downstream/action.yml

@@ -16,14 +16,24 @@ runs:
     - name: set up venv
       shell: bash
       run: |
+          set -x
+          # Set up env values
           package_spec="${{inputs.package_spec}}"
           package_spec=${package_spec:-"${{inputs.package_name}}[test]"}
           pytest_args="${{inputs.pytest_args}}"
           pytest_args=${pytest_args:-"--pyargs ${{inputs.package_name}}"}
+          env_values=${{ inputs.env_values }}
+          env_values=${package_spec:-"FIZZ=BUZZ"}
+
+          # Set up venv
           python -m venv test_venv
           bin_dir=./test_venv/bin
           ${bin_dir}/python -m pip install -U pip
           ${bin_dir}/python -m pip install ${package_spec}
           ${bin_dir}/python -m pip install . --force-reinstall
-          ${{ inputs.env_values }}; ${bin_dir}/pytest ${pytest_args}
+
+          # Test the downstream package
+          ${env_values}; ${bin_dir}/pytest ${pytest_args}
+
+          # Cleanup
           rm -rf ./test_venv