n = test_rng_uniform_int(rng, 10)+1;
str = malloc_nofail(n+1);
/* Exclude 10 digits from the first character. */
str[0] = valid[test_rng_uniform_int(rng, sizeof valid - 10)];
n = test_rng_uniform_int(rng, 10)+1;
str = malloc_nofail(n+1);
/* Exclude 10 digits from the first character. */
str[0] = valid[test_rng_uniform_int(rng, sizeof valid - 10)];