diff --git a/scripts/setup-helper-functions.sh b/scripts/setup-helper-functions.sh
index ab0c463c40a3..127dea70c0f9 100755
--- a/scripts/setup-helper-functions.sh
+++ b/scripts/setup-helper-functions.sh
@@ -160,7 +160,7 @@ function wget_and_untar {
 }
 
 function cmake_install {
-  if [ -n "$1" ]; then
+  if [ -d "$1" ]; then
     DIR="$1"
     shift
   else