diff --git a/tests/ci/tee_popen.py b/tests/ci/tee_popen.py
index 7270cd6fb03..61404847bff 100644
--- a/tests/ci/tee_popen.py
+++ b/tests/ci/tee_popen.py
@@ -3,6 +3,7 @@
 from subprocess import Popen, PIPE, STDOUT
 from threading import Thread
 from time import sleep
+from typing import Optional
 import logging
 import os
 import sys
@@ -18,7 +19,7 @@ class TeePopen:
         self.command = command
         self.log_file = log_file
         self.env = env
-        self.process = None
+        self._process = None  # type: Optional[Popen]
         self.timeout = timeout
 
     def _check_timeout(self):
@@ -51,7 +52,7 @@ class TeePopen:
         return self
 
     def __exit__(self, t, value, traceback):
-        for line in self.process.stdout:
+        for line in self.process.stdout:  # type: ignore
             sys.stdout.write(line)
             self.log_file.write(line)
 
@@ -59,8 +60,18 @@ class TeePopen:
         self.log_file.close()
 
     def wait(self):
-        for line in self.process.stdout:
+        for line in self.process.stdout:  # type: ignore
             sys.stdout.write(line)
             self.log_file.write(line)
 
         return self.process.wait()
+
+    @property
+    def process(self) -> Popen:
+        if self._process is not None:
+            return self._process
+        raise AttributeError("process is not created yet")
+
+    @process.setter
+    def process(self, process: Popen) -> None:
+        self._process = process