fc8dc48020
git-subtree-dir: third_party/abseil_cpp git-subtree-mainline:ffb2ae54begit-subtree-split:768eb2ca28
127 lines
3.5 KiB
C++
127 lines
3.5 KiB
C++
// Copyright 2017 The Abseil Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "absl/random/seed_sequences.h"
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#include <iterator>
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#include <random>
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#include "gmock/gmock.h"
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#include "gtest/gtest.h"
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#include "absl/random/internal/nonsecure_base.h"
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#include "absl/random/random.h"
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namespace {
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TEST(SeedSequences, Examples) {
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{
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absl::SeedSeq seed_seq({1, 2, 3});
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absl::BitGen bitgen(seed_seq);
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EXPECT_NE(0, bitgen());
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}
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{
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absl::BitGen engine;
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auto seed_seq = absl::CreateSeedSeqFrom(&engine);
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absl::BitGen bitgen(seed_seq);
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EXPECT_NE(engine(), bitgen());
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}
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{
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auto seed_seq = absl::MakeSeedSeq();
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std::mt19937 random(seed_seq);
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EXPECT_NE(0, random());
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}
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}
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TEST(CreateSeedSeqFrom, CompatibleWithStdTypes) {
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using ExampleNonsecureURBG =
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absl::random_internal::NonsecureURBGBase<std::minstd_rand0>;
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// Construct a URBG instance.
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ExampleNonsecureURBG rng;
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// Construct a Seed Sequence from its variates.
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auto seq_from_rng = absl::CreateSeedSeqFrom(&rng);
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// Ensure that another URBG can be validly constructed from the Seed Sequence.
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std::mt19937_64{seq_from_rng};
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}
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TEST(CreateSeedSeqFrom, CompatibleWithBitGenerator) {
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// Construct a URBG instance.
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absl::BitGen rng;
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// Construct a Seed Sequence from its variates.
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auto seq_from_rng = absl::CreateSeedSeqFrom(&rng);
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// Ensure that another URBG can be validly constructed from the Seed Sequence.
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std::mt19937_64{seq_from_rng};
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}
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TEST(CreateSeedSeqFrom, CompatibleWithInsecureBitGen) {
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// Construct a URBG instance.
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absl::InsecureBitGen rng;
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// Construct a Seed Sequence from its variates.
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auto seq_from_rng = absl::CreateSeedSeqFrom(&rng);
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// Ensure that another URBG can be validly constructed from the Seed Sequence.
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std::mt19937_64{seq_from_rng};
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}
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TEST(CreateSeedSeqFrom, CompatibleWithRawURBG) {
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// Construct a URBG instance.
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std::random_device urandom;
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// Construct a Seed Sequence from its variates, using 64b of seed-material.
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auto seq_from_rng = absl::CreateSeedSeqFrom(&urandom);
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// Ensure that another URBG can be validly constructed from the Seed Sequence.
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std::mt19937_64{seq_from_rng};
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}
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template <typename URBG>
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void TestReproducibleVariateSequencesForNonsecureURBG() {
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const size_t kNumVariates = 1000;
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// Master RNG instance.
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URBG rng;
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// Reused for both RNG instances.
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auto reusable_seed = absl::CreateSeedSeqFrom(&rng);
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typename URBG::result_type variates[kNumVariates];
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{
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URBG child(reusable_seed);
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for (auto& variate : variates) {
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variate = child();
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}
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}
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// Ensure that variate-sequence can be "replayed" by identical RNG.
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{
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URBG child(reusable_seed);
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for (auto& variate : variates) {
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ASSERT_EQ(variate, child());
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}
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}
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}
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TEST(CreateSeedSeqFrom, ReproducesVariateSequencesForInsecureBitGen) {
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TestReproducibleVariateSequencesForNonsecureURBG<absl::InsecureBitGen>();
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}
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TEST(CreateSeedSeqFrom, ReproducesVariateSequencesForBitGenerator) {
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TestReproducibleVariateSequencesForNonsecureURBG<absl::BitGen>();
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}
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} // namespace
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