cat process replay diff (#1112)

* cat process replay diff

* always

.github/workflows/test.yaml

@@ -15,7 +15,8 @@ jobs:
     - name: Checkout submodules
       run: |
         git submodule update --init
-    - run: |
+    - name: Build docker image
+      run: |
         docker pull $(grep -ioP '(?<=^from)\s+\S+' Dockerfile.openpilot) || true
         docker pull docker.io/commaai/openpilot:latest || true
 
@@ -98,6 +99,9 @@ jobs:
           docker run --shm-size 1G --name ${CONTAINER_NAME} tmppilot /bin/sh -c "cd /tmp/openpilot/selfdrive/test/process_replay && CI=1 ./test_processes.py"
           docker cp $CONTAINER_NAME:/tmp/openpilot/selfdrive/test/process_replay/diff.txt diff.txt
           docker rm $CONTAINER_NAME
+      - name: Print diff
+        if: always()
+        run: cat diff.txt
       - uses: actions/upload-artifact@v1
         if: always()
         with: