esp-idf/components/esp_hw_support/test/test_random.c

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#include <stdio.h>
#include <string.h>
#include "unity.h"
#include "esp_system.h"
/* Note: these are just sanity tests, not the same as
entropy tests
*/
TEST_CASE("call esp_random()", "[random]")
{
const size_t NUM_RANDOM = 128; /* in most cases this is massive overkill */
uint32_t zeroes = UINT32_MAX;
uint32_t ones = 0;
for (int i = 0; i < NUM_RANDOM - 1; i++) {
uint32_t r = esp_random();
ones |= r;
zeroes &= ~r;
}
/* assuming a 'white' random distribution, we can expect
usually at least one time each bit will be zero and at
least one time each will be one. Statistically this
can still fail, just *very* unlikely to. */
TEST_ASSERT_EQUAL_HEX32(0, zeroes);
TEST_ASSERT_EQUAL_HEX32(UINT32_MAX, ones);
}
TEST_CASE("call esp_fill_random()", "[random]")
{
const size_t NUM_BUF = 200;
const size_t BUF_SZ = 16;
uint8_t buf[NUM_BUF][BUF_SZ];
uint8_t zero_buf[BUF_SZ];
uint8_t one_buf[BUF_SZ];
bzero(buf, sizeof(buf));
bzero(one_buf, sizeof(zero_buf));
memset(zero_buf, 0xFF, sizeof(one_buf));
for (int i = 0; i < NUM_BUF; i++) {
esp_fill_random(buf[i], BUF_SZ);
}
/* No two 128-bit buffers should be the same
(again, statistically this could happen but it's very unlikely) */
for (int i = 0; i < NUM_BUF; i++) {
for (int j = 0; j < NUM_BUF; j++) {
if (i != j) {
TEST_ASSERT_NOT_EQUAL(0, memcmp(buf[i], buf[j], BUF_SZ));
}
}
}
/* Do the same all bits are zero and one at least once test across the buffers */
for (int i = 0; i < NUM_BUF; i++) {
for (int x = 0; x < BUF_SZ; x++) {
zero_buf[x] &= ~buf[i][x];
one_buf[x] |= buf[i][x];
}
}
for (int x = 0; x < BUF_SZ; x++) {
TEST_ASSERT_EQUAL_HEX8(0, zero_buf[x]);
TEST_ASSERT_EQUAL_HEX8(0xFF, one_buf[x]);
}
}