diff --git a/tests/cases/unittests/cachingInServerLSHost.ts b/tests/cases/unittests/cachingInServerLSHost.ts
index ff2da76ba4..88b44a693b 100644
--- a/tests/cases/unittests/cachingInServerLSHost.ts
+++ b/tests/cases/unittests/cachingInServerLSHost.ts
@@ -45,6 +45,11 @@ module ts {
                 return {
                     close: () => { }
                 }
+            },
+            watchDirectory: (path, callback, recursive?) => {
+                return {
+                    close: () => { }
+                }
             }
         };
     }