diff --git a/tests/pytest/util/dnodes.py b/tests/pytest/util/dnodes.py
index d63e72e8fc7cabcc5aab1c2b73db9c13e1939185..4a35a019cf7cebd03f7f2091178ae1cb71aadff8 100644
--- a/tests/pytest/util/dnodes.py
+++ b/tests/pytest/util/dnodes.py
@@ -43,6 +43,7 @@ class TDSimClient:
             "qdebugFlag": "135",
             "telemetryReporting": "0",
             "enableCoreFile": "1",
+            "defaultJSONStrType": "binary",
         }
 
     def getLogDir(self):