diff --git a/tests/include/test/helpers.h b/tests/include/test/helpers.h
index 2d53cf9..134e49b 100644
--- a/tests/include/test/helpers.h
+++ b/tests/include/test/helpers.h
@@ -65,7 +65,7 @@
  *
  * For convenience, dies if allocation fails.
  */
-unsigned char *zero_alloc( size_t len );
+unsigned char *mbedtls_test_zero_alloc( size_t len );
 
 /**
  * Allocate and fill a buffer from hex data.