diff --git a/hashing/sha256.cpp b/hashing/sha256.cpp
index 674111a89..514fffa9f 100644
--- a/hashing/sha256.cpp
+++ b/hashing/sha256.cpp
@@ -308,7 +308,7 @@ void test_sha256() {
     }
 }
 
-void test() {
+static void test() {
     test_compute_padded_size();
     test_extract_byte();
     test_get_char();