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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
#include "mozilla/RandomNum.h"
#include <vector>
/*
* We're going to check that random number generation is sane on a basic
* level - That is, we want to check that the function returns success
* and doesn't just keep returning the same number.
*
* Note that there are many more tests that could be done, but to really test
* a PRNG we'd probably need to generate a large set of randoms and
* perform statistical analysis on them. Maybe that's worth doing eventually?
*
* For now we should be fine just performing a dumb test of generating 5
* numbers and making sure they're all unique. In theory, it is possible for
* this test to report a false negative, but with 5 numbers the probability
* is less than one-in-a-trillion.
*
*/
#define NUM_RANDOMS_TO_GENERATE 5
using mozilla::Maybe;
using mozilla::RandomUint64;
static uint64_t getRandomUint64OrDie() {
Maybe<uint64_t> maybeRandomNum = RandomUint64();
MOZ_RELEASE_ASSERT(maybeRandomNum.isSome());
return maybeRandomNum.value();
}
static void TestRandomUint64() {
// The allocator uses RandomNum.h too, but its initialization path allocates
// memory. While the allocator itself handles the situation, we can't, so
// we make sure to use an allocation before getting a Random number ourselves.
std::vector<uint64_t> randomsList;
randomsList.reserve(NUM_RANDOMS_TO_GENERATE);
for (uint8_t i = 0; i < NUM_RANDOMS_TO_GENERATE; ++i) {
uint64_t randomNum = getRandomUint64OrDie();
for (uint64_t num : randomsList) {
MOZ_RELEASE_ASSERT(randomNum != num);
}
randomsList.push_back(randomNum);
}
}
int main() {
TestRandomUint64();
return 0;
}