test: verify gateway spool is drained

tools/test_go_systemd_prod_smoke.py

@@ -66,6 +66,18 @@ LISTEN 0 4096 *:20210 *:* users:(("realtime-api",pid=11,fd=3))
         self.assertEqual(by_name["port.808"].status, "fail")
         self.assertIn("java", by_name["port.808"].message)
 
+    def test_spool_check_passes_when_no_pending_files(self):
+        check = smoke.spool_check("files=0 bytes=208896 recent=0")
+
+        self.assertEqual(check.status, "pass")
+        self.assertIn("files=0", check.message)
+
+    def test_spool_check_fails_when_pending_or_recent_files_exist(self):
+        for output in ["files=2 bytes=300 recent=0", "files=0 bytes=208896 recent=1"]:
+            check = smoke.spool_check(output)
+
+            self.assertEqual(check.status, "fail")
+
 
 if __name__ == "__main__":
     unittest.main()