fixup! fixup! TST: add a job without dependency groups

Author: neutrinoceros

.github/workflows/test_action.yml

@@ -43,4 +43,4 @@ jobs:
         with:
           pure_python_wheel: true
           test_extras: recommended
-          test_command: ''
+          test_command: python -c 'import test_package'

action.yml

@@ -60,6 +60,7 @@ runs:
     shell: bash
     run: |
       echo "group_flags=$( python -c "print(' '.join(f'--group {g.strip()}' for g in '${{ inputs.test_groups }}'.split(',')))" ) " >> "$GITHUB_ENV"
+    if: ${{ inputs.test_groups != '' }}
 
   - name: Test source distribution
     shell: bash