diff --git a/tests/cases/unittests/cachingInServerLSHost.ts b/tests/cases/unittests/cachingInServerLSHost.ts
index c8e7aa834cc..17de3c6de02 100644
--- a/tests/cases/unittests/cachingInServerLSHost.ts
+++ b/tests/cases/unittests/cachingInServerLSHost.ts
@@ -61,12 +61,8 @@ namespace ts {
                     close: () => { }
                 };
             },
-            setTimeout: (callback, ms, ...args) => {
-                return setTimeout(callback, ms, args);
-            },
-            clearTimeout: (timeoutId) => {
-                clearTimeout(timeoutId);
-            }
+            setTimeout,
+            clearTimeout
         };
     }