diff --git a/tests/suites/test_suite_gcm.function b/tests/suites/test_suite_gcm.function
index e7b024e..43c11c3 100644
--- a/tests/suites/test_suite_gcm.function
+++ b/tests/suites/test_suite_gcm.function
@@ -627,7 +627,7 @@
      * Therefore we must ensure we round up to the nearest 128-bits/16-bytes.
      */
     buffer_len = src_str->len;
-    if (buffer_len % 16 != 0) {
+    if (buffer_len % 16 != 0 || buffer_len == 0) {
         buffer_len += (16 - (buffer_len % 16));
     }
     TEST_CALLOC(buffer, buffer_len);
@@ -686,7 +686,7 @@
      * Therefore we must ensure we round up to the nearest 128-bits/16-bytes.
      */
     buffer_len = src_str->len;
-    if (buffer_len % 16 != 0) {
+    if (buffer_len % 16 != 0 || buffer_len == 0) {
         buffer_len += (16 - (buffer_len % 16));
     }
     TEST_CALLOC(buffer, buffer_len);