| /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
| |
| #include <math.h> |
| |
| #include "hexdecoct.h" |
| #include "log.h" |
| #include "memory-util.h" |
| #include "random-util.h" |
| #include "terminal-util.h" |
| #include "tests.h" |
| |
| TEST(random_bytes) { |
| uint8_t buf[16] = {}; |
| |
| for (size_t i = 1; i < sizeof buf; i++) { |
| random_bytes(buf, i); |
| if (i + 1 < sizeof buf) |
| assert_se(buf[i] == 0); |
| |
| hexdump(stdout, buf, i); |
| } |
| } |
| |
| TEST(crypto_random_bytes) { |
| uint8_t buf[16] = {}; |
| |
| for (size_t i = 1; i < sizeof buf; i++) { |
| assert_se(crypto_random_bytes(buf, i) == 0); |
| if (i + 1 < sizeof buf) |
| assert_se(buf[i] == 0); |
| |
| hexdump(stdout, buf, i); |
| } |
| } |
| |
| #define TOTAL 100000 |
| |
| static void test_random_u64_range_one(unsigned mod) { |
| log_info("/* %s(%u) */", __func__, mod); |
| |
| unsigned max = 0, count[mod]; |
| zero(count); |
| |
| for (unsigned i = 0; i < TOTAL; i++) { |
| uint64_t x; |
| |
| x = random_u64_range(mod); |
| |
| count[x]++; |
| max = MAX(max, count[x]); |
| } |
| |
| /* Print histogram: vertical axis — value, horizontal axis — count. |
| * |
| * The expected value is always TOTAL/mod, because the distribution should be flat. The expected |
| * variance is TOTAL×p×(1-p), where p==1/mod, and standard deviation the root of the variance. |
| * Assert that the deviation from the expected value is less than 6 standard deviations. |
| */ |
| unsigned scale = 2 * max / (columns() < 20 ? 80 : columns() - 20); |
| double exp = (double) TOTAL / mod; |
| |
| for (size_t i = 0; i < mod; i++) { |
| double dev = (count[i] - exp) / sqrt(exp * (mod > 1 ? mod - 1 : 1) / mod); |
| log_debug("%02zu: %5u (%+.3f)%*s", |
| i, count[i], dev, |
| (int) (count[i] / scale), "x"); |
| |
| assert_se(fabs(dev) < 6); /* 6 sigma is excessive, but this check should be enough to |
| * identify catastrophic failure while minimizing false |
| * positives. */ |
| } |
| } |
| |
| TEST(random_u64_range) { |
| for (unsigned mod = 1; mod < 29; mod++) |
| test_random_u64_range_one(mod); |
| } |
| |
| DEFINE_TEST_MAIN(LOG_DEBUG); |