Test jupyter_kernel_test as downstream

Author: blink1073

.github/workflows/downstream.yml

@@ -42,3 +42,9 @@ jobs:
       - name: Test jupyter_client
         if: ${{ always() }}
         run: pytest --pyargs jupyter_client
+      - name: Test jupyter_kernel_test
+        run:
+          git clone [email protected]:jupyter/jupyter_kernel_test.git
+          cd jupyter_kernel_test
+          pip install -e ".[test]"
+          python test_ipykernel.py