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Diffstat (limited to 'absl/random/internal/explicit_seed_seq_test.cc')
| -rw-r--r-- | absl/random/internal/explicit_seed_seq_test.cc | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/absl/random/internal/explicit_seed_seq_test.cc b/absl/random/internal/explicit_seed_seq_test.cc new file mode 100644 index 00000000..a55ad739 --- /dev/null +++ b/absl/random/internal/explicit_seed_seq_test.cc @@ -0,0 +1,204 @@ +// Copyright 2017 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#include "absl/random/internal/explicit_seed_seq.h" + +#include <iterator> +#include <random> +#include <utility> + +#include "gmock/gmock.h" +#include "gtest/gtest.h" +#include "absl/random/seed_sequences.h" + +namespace { + +template <typename Sseq> +bool ConformsToInterface() { + // Check that the SeedSequence can be default-constructed. + { Sseq default_constructed_seq; } + // Check that the SeedSequence can be constructed with two iterators. + { + uint32_t init_array[] = {1, 3, 5, 7, 9}; + Sseq iterator_constructed_seq(init_array, &init_array[5]); + } + // Check that the SeedSequence can be std::initializer_list-constructed. + { Sseq list_constructed_seq = {1, 3, 5, 7, 9, 11, 13}; } + // Check that param() and size() return state provided to constructor. + { + uint32_t init_array[] = {1, 2, 3, 4, 5}; + Sseq seq(init_array, &init_array[ABSL_ARRAYSIZE(init_array)]); + EXPECT_EQ(seq.size(), ABSL_ARRAYSIZE(init_array)); + + uint32_t state_array[ABSL_ARRAYSIZE(init_array)]; + seq.param(state_array); + + for (int i = 0; i < ABSL_ARRAYSIZE(state_array); i++) { + EXPECT_EQ(state_array[i], i + 1); + } + } + // Check for presence of generate() method. + { + Sseq seq; + uint32_t seeds[5]; + + seq.generate(seeds, &seeds[ABSL_ARRAYSIZE(seeds)]); + } + return true; +} +} // namespace + +TEST(SeedSequences, CheckInterfaces) { + // Control case + EXPECT_TRUE(ConformsToInterface<std::seed_seq>()); + + // Abseil classes + EXPECT_TRUE(ConformsToInterface<absl::random_internal::ExplicitSeedSeq>()); +} + +TEST(ExplicitSeedSeq, DefaultConstructorGeneratesZeros) { + const size_t kNumBlocks = 128; + + uint32_t outputs[kNumBlocks]; + absl::random_internal::ExplicitSeedSeq seq; + seq.generate(outputs, &outputs[kNumBlocks]); + + for (uint32_t& seed : outputs) { + EXPECT_EQ(seed, 0); + } +} + +TEST(ExplicitSeeqSeq, SeedMaterialIsForwardedIdentically) { + const size_t kNumBlocks = 128; + + uint32_t seed_material[kNumBlocks]; + std::random_device urandom{"/dev/urandom"}; + for (uint32_t& seed : seed_material) { + seed = urandom(); + } + absl::random_internal::ExplicitSeedSeq seq(seed_material, + &seed_material[kNumBlocks]); + + // Check that output is same as seed-material provided to constructor. + { + const size_t kNumGenerated = kNumBlocks / 2; + uint32_t outputs[kNumGenerated]; + seq.generate(outputs, &outputs[kNumGenerated]); + for (size_t i = 0; i < kNumGenerated; i++) { + EXPECT_EQ(outputs[i], seed_material[i]); + } + } + // Check that SeedSequence is stateless between invocations: Despite the last + // invocation of generate() only consuming half of the input-entropy, the same + // entropy will be recycled for the next invocation. + { + const size_t kNumGenerated = kNumBlocks; + uint32_t outputs[kNumGenerated]; + seq.generate(outputs, &outputs[kNumGenerated]); + for (size_t i = 0; i < kNumGenerated; i++) { + EXPECT_EQ(outputs[i], seed_material[i]); + } + } + // Check that when more seed-material is asked for than is provided, nonzero + // values are still written. + { + const size_t kNumGenerated = kNumBlocks * 2; + uint32_t outputs[kNumGenerated]; + seq.generate(outputs, &outputs[kNumGenerated]); + for (size_t i = 0; i < kNumGenerated; i++) { + EXPECT_EQ(outputs[i], seed_material[i % kNumBlocks]); + } + } +} + +TEST(ExplicitSeedSeq, CopyAndMoveConstructors) { + using testing::Each; + using testing::Eq; + using testing::Not; + using testing::Pointwise; + + uint32_t entropy[4]; + std::random_device urandom("/dev/urandom"); + for (uint32_t& entry : entropy) { + entry = urandom(); + } + absl::random_internal::ExplicitSeedSeq seq_from_entropy(std::begin(entropy), + std::end(entropy)); + // Copy constructor. + { + absl::random_internal::ExplicitSeedSeq seq_copy(seq_from_entropy); + EXPECT_EQ(seq_copy.size(), seq_from_entropy.size()); + + std::vector<uint32_t> seeds_1; + seeds_1.resize(1000, 0); + std::vector<uint32_t> seeds_2; + seeds_2.resize(1000, 1); + + seq_from_entropy.generate(seeds_1.begin(), seeds_1.end()); + seq_copy.generate(seeds_2.begin(), seeds_2.end()); + + EXPECT_THAT(seeds_1, Pointwise(Eq(), seeds_2)); + } + // Assignment operator. + { + for (uint32_t& entry : entropy) { + entry = urandom(); + } + absl::random_internal::ExplicitSeedSeq another_seq(std::begin(entropy), + std::end(entropy)); + + std::vector<uint32_t> seeds_1; + seeds_1.resize(1000, 0); + std::vector<uint32_t> seeds_2; + seeds_2.resize(1000, 0); + + seq_from_entropy.generate(seeds_1.begin(), seeds_1.end()); + another_seq.generate(seeds_2.begin(), seeds_2.end()); + + // Assert precondition: Sequences generated by seed-sequences are not equal. + EXPECT_THAT(seeds_1, Not(Pointwise(Eq(), seeds_2))); + + // Apply the assignment-operator. + another_seq = seq_from_entropy; + + // Re-generate seeds. + seq_from_entropy.generate(seeds_1.begin(), seeds_1.end()); + another_seq.generate(seeds_2.begin(), seeds_2.end()); + + // Seeds generated by seed-sequences should now be equal. + EXPECT_THAT(seeds_1, Pointwise(Eq(), seeds_2)); + } + // Move constructor. + { + // Get seeds from seed-sequence constructed from entropy. + std::vector<uint32_t> seeds_1; + seeds_1.resize(1000, 0); + seq_from_entropy.generate(seeds_1.begin(), seeds_1.end()); + + // Apply move-constructor move the sequence to another instance. + absl::random_internal::ExplicitSeedSeq moved_seq( + std::move(seq_from_entropy)); + std::vector<uint32_t> seeds_2; + seeds_2.resize(1000, 1); + moved_seq.generate(seeds_2.begin(), seeds_2.end()); + // Verify that seeds produced by moved-instance are the same as original. + EXPECT_THAT(seeds_1, Pointwise(Eq(), seeds_2)); + + // Verify that the moved-from instance now behaves like a + // default-constructed instance. + EXPECT_EQ(seq_from_entropy.size(), 0); + seq_from_entropy.generate(seeds_1.begin(), seeds_1.end()); + EXPECT_THAT(seeds_1, Each(Eq(0))); + } +} |