[Mod] change working path when MainEngine created

vnpy/trader/engine.py

@@ -3,6 +3,7 @@
 
 import logging
 import smtplib
+import os
 from abc import ABC
 from datetime import datetime
 from email.message import EmailMessage
@@ -30,7 +31,7 @@ from .object import (
     HistoryRequest
 )
 from .setting import SETTINGS
-from .utility import get_folder_path
+from .utility import get_folder_path, TRADER_DIR
 
 
 class MainEngine:
@@ -51,7 +52,8 @@ class MainEngine:
         self.apps = {}
         self.exchanges = []
 
-        self.init_engines()
+        os.chdir(TRADER_DIR)    # Change working directory
+        self.init_engines()     # Initialize function engines
 
     def add_engine(self, engine_class: Any):
         """