diff --git a/data_structures/trie_tree.cpp b/data_structures/trie_tree.cpp
index 9a4931c20..d299d176d 100644
--- a/data_structures/trie_tree.cpp
+++ b/data_structures/trie_tree.cpp
@@ -149,7 +149,7 @@ class trie {
  * @brief Testing function
  * @returns void
  */
-void test() {
+static void test() {
     trie root;
     root.insert("hello");
     root.insert("world");