diff --git a/admin/scripts/test-release.sh b/admin/scripts/test-release.sh
index 09637a3ed141..f3e678756392 100755
--- a/admin/scripts/test-release.sh
+++ b/admin/scripts/test-release.sh
@@ -27,7 +27,7 @@ git diff --name-only -- '*.json' | sed 's, ,\\&,g' | xargs git checkout --
 npm_config_registry="$CUSTOM_REGISTRY_URL" npx @docusaurus/init@"$NEW_VERSION" init test-website classic
 
 # Stop Docker container
-if (! $KEEP_CONTAINER) && ( $(docker container inspect "$CONTAINER_NAME" > /dev/null 2>&1) ); then
+if [[ -z "${KEEP_CONTAINER:-}" ]] && ( $(docker container inspect "$CONTAINER_NAME" > /dev/null 2>&1) ); then
   # Remove Docker container
   docker container stop $CONTAINER_NAME > /dev/null
 fi