diff --git a/tests/suites/test_suite_pem.function b/tests/suites/test_suite_pem.function
index 36801d14a1..b3b3e8d28a 100644
--- a/tests/suites/test_suite_pem.function
+++ b/tests/suites/test_suite_pem.function
@@ -35,7 +35,7 @@ exit:
 /* BEGIN_CASE depends_on:MBEDTLS_PEM_WRITE_C */
 void mbedtls_pem_write_buffer_lengths()
 {
-    unsigned char data[256] = {};
+    unsigned char data[256] = { 0 };
     unsigned char buf[1024];
     size_t olen_needed, olen;
     int ret;