Add test case for negative number with highest bit of top octet set

This currently adds an incorrect 00: padding, consistent with OpenSSL's
behavior.

diff --git a/regress/lib/libcrypto/bn/bn_print.c b/regress/lib/libcrypto/bn/bn_print.c
index 24f261d..47def85 100644 (file)
--- a/regress/lib/libcrypto/bn/bn_print.c
+++ b/regress/lib/libcrypto/bn/bn_print.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: bn_print.c,v 1.3 2023/07/07 07:47:25 tb Exp $ */
+/*     $OpenBSD: bn_print.c,v 1.4 2023/07/10 20:21:37 tb Exp $ */
 
 /*
  * Copyright (c) 2023 Theo Buehler <tb@openbsd.org>
@@ -139,6 +139,11 @@ const struct print_test {
                .want = "    mana mana\n"
                        "        00:80:00:00:00:00:00:00:00:00\n",
        },
+       {
+               .desc = "high bit of first nibble is set for negative number",
+               .want = "    mana mana (Negative)\n"
+                       "        00:80:00:00:00:00:00:00:00:00\n",
+       },
 };
 
 #define N_TESTCASES    (sizeof(bn_print_tests) / sizeof(bn_print_tests[0]))
@@ -281,6 +286,13 @@ main(void)
        test = &bn_print_tests[testcase++];
        failed |= bn_print_testcase(bn, test);
 
+       /* high bit of first nibble is set for negative number. */
+       BN_set_negative(bn, 1);
+       if (testcase >= N_TESTCASES)
+               errx(1, "Too many tests");
+       test = &bn_print_tests[testcase++];
+       failed |= bn_print_testcase(bn, test);
+
        if (testcase != N_TESTCASES) {
                warnx("Not all tests run");
                failed |= 1;