diff --git a/test/default/ed25519_convert.c b/test/default/ed25519_convert.c
index c65b9906..f7af0adf 100644
--- a/test/default/ed25519_convert.c
+++ b/test/default/ed25519_convert.c
@@ -45,6 +45,18 @@ main(void)
             printf("conversion failed\n");
         }
     }
+
+    sodium_hex2bin(ed25519_pk, crypto_sign_ed25519_PUBLICKEYBYTES,
+                   "0000000000000000000000000000000000000000000000000000000000000000"
+                   "0000000000000000000000000000000000000000000000000000000000000000",
+                   64, NULL, NULL, NULL);
+    assert(crypto_sign_ed25519_pk_to_curve25519(curve25519_pk, ed25519_pk) == -1);
+    sodium_hex2bin(ed25519_pk, crypto_sign_ed25519_PUBLICKEYBYTES,
+                   "0500000000000000000000000000000000000000000000000000000000000000"
+                   "0000000000000000000000000000000000000000000000000000000000000000",
+                   64, NULL, NULL, NULL);
+    assert(crypto_sign_ed25519_pk_to_curve25519(curve25519_pk, ed25519_pk) == -1);
+
     printf("ok\n");
 
     return 0;