diff --git a/ynh-dev b/ynh-dev
index c092549..4c51ad2 100755
--- a/ynh-dev
+++ b/ynh-dev
@@ -326,7 +326,7 @@ elif [ "$1" = "test" ]; then
                 PIP_DEPENDENCIES="pytest-mock requests-mock"
                 for DEP in $PIP_DEPENDENCIES
                 do
-                    if [ -z `pip show $DEP` ]; then
+                    if [ -z "$(pip show $DEP)" ]; then
                         echo "======================="
                         echo "Installing $DEP with pip"
                         echo "======================="