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