Notify Zulip chat on integration test failure

.github/workflows/integration_test.yaml

@@ -25,3 +25,20 @@ jobs:
       - name: Test with tox
         run: |
           tox -e int
+
+      - name: Notify on failure
+        if: ${{ failure() }}
+        env:
+          ZULIP_BOT_CREDENTIALS: ${{ secrets.ZULIP_BOT_CREDENTIALS }}
+        run: |
+          if [ -z "${ZULIP_BOT_CREDENTIALS}" ]; then
+            echo "Skipping notify, ZULIP_BOT_CREDENTIALS is unset"
+            exit 0
+          fi
+
+          curl -X POST https://beets.zulipchat.com/api/v1/messages \
+            -u "${ZULIP_BOT_CREDENTIALS}" \
+            -d "type=stream" \
+            -d "to=general" \
+            -d "subject=${GITHUB_WORKFLOW} - $(date -u +%Y-%m-%d)" \
+            -d "content=[${GITHUB_WORKFLOW}#${GITHUB_RUN_NUMBER}](${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}/actions/runs/${GITHUB_RUN_ID}) failed."