diff --git a/server/tests/conftest.py b/server/tests/conftest.py
index d99771f8..98222792 100644
--- a/server/tests/conftest.py
+++ b/server/tests/conftest.py
@@ -2,7 +2,7 @@ import pytest
 import os
 from text_generation_server.pb import generate_pb2
 
-os.environ["USE_PREFIX_CACHING"] = "1"
+os.environ["PREFIX_CACHING"] = "1"
 os.environ["ATTENTION"] = "flashinfer"