diff --git a/test/default/sodium_utils.c b/test/default/sodium_utils.c
index 06e9615a..d748f1ef 100644
--- a/test/default/sodium_utils.c
+++ b/test/default/sodium_utils.c
@@ -294,6 +294,8 @@ main(void)
 
         assert(sodium_pad(&bin_padded_len, bin_padded, bin_len,
                           blocksize, bin_padded_maxlen - 1U) == -1);
+        assert(sodium_pad(NULL, bin_padded, bin_len,
+                          blocksize, bin_padded_maxlen + 1U) == 0);
         assert(sodium_pad(&bin_padded_len, bin_padded, bin_len,
                           blocksize, bin_padded_maxlen + 1U) == 0);
         assert(sodium_pad(&bin_padded_len, bin_padded, bin_len,