Function test_save_env

tests/ds4_test.c:41–50

    char *end = NULL;
    unsigned long long n = strtoull(v, &end, 10);
    if (end == v || n == 0) return 0;
    const uint64_t one_gib = 1024ull * 1024ull * 1024ull;
    if (n > UINT64_MAX / one_gib) return UINT64_MAX;
    return (uint64_t)n * one_gib;
}

static char *test_save_env(const char *name) {
    const char *value = getenv(name);
    if (!value) return NULL;
    size_t len = strlen(value);
    char *copy = malloc(len + 1);
    TEST_ASSERT(copy != NULL);
    if (!copy) return NULL;