summaryrefslogtreecommitdiff
path: root/absl/random/internal/seed_material_test.cc
diff options
context:
space:
mode:
Diffstat (limited to 'absl/random/internal/seed_material_test.cc')
-rw-r--r--absl/random/internal/seed_material_test.cc202
1 files changed, 202 insertions, 0 deletions
diff --git a/absl/random/internal/seed_material_test.cc b/absl/random/internal/seed_material_test.cc
new file mode 100644
index 00000000..6db2820e
--- /dev/null
+++ b/absl/random/internal/seed_material_test.cc
@@ -0,0 +1,202 @@
+// 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/seed_material.h"
+
+#include <bitset>
+#include <cstdlib>
+#include <cstring>
+#include <random>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+
+#ifdef __ANDROID__
+// Android assert messages only go to system log, so death tests cannot inspect
+// the message for matching.
+#define ABSL_EXPECT_DEATH_IF_SUPPORTED(statement, regex) \
+ EXPECT_DEATH_IF_SUPPORTED(statement, ".*")
+#else
+#define ABSL_EXPECT_DEATH_IF_SUPPORTED(statement, regex) \
+ EXPECT_DEATH_IF_SUPPORTED(statement, regex)
+#endif
+
+namespace {
+
+using testing::Each;
+using testing::ElementsAre;
+using testing::Eq;
+using testing::Ne;
+using testing::Pointwise;
+
+TEST(SeedBitsToBlocks, VerifyCases) {
+ EXPECT_EQ(0, absl::random_internal::SeedBitsToBlocks(0));
+ EXPECT_EQ(1, absl::random_internal::SeedBitsToBlocks(1));
+ EXPECT_EQ(1, absl::random_internal::SeedBitsToBlocks(31));
+ EXPECT_EQ(1, absl::random_internal::SeedBitsToBlocks(32));
+ EXPECT_EQ(2, absl::random_internal::SeedBitsToBlocks(33));
+ EXPECT_EQ(4, absl::random_internal::SeedBitsToBlocks(127));
+ EXPECT_EQ(4, absl::random_internal::SeedBitsToBlocks(128));
+ EXPECT_EQ(5, absl::random_internal::SeedBitsToBlocks(129));
+}
+
+TEST(ReadSeedMaterialFromOSEntropy, SuccessiveReadsAreDistinct) {
+ constexpr size_t kSeedMaterialSize = 64;
+ uint32_t seed_material_1[kSeedMaterialSize] = {};
+ uint32_t seed_material_2[kSeedMaterialSize] = {};
+
+ EXPECT_TRUE(absl::random_internal::ReadSeedMaterialFromOSEntropy(
+ absl::Span<uint32_t>(seed_material_1, kSeedMaterialSize)));
+ EXPECT_TRUE(absl::random_internal::ReadSeedMaterialFromOSEntropy(
+ absl::Span<uint32_t>(seed_material_2, kSeedMaterialSize)));
+
+ EXPECT_THAT(seed_material_1, Pointwise(Ne(), seed_material_2));
+}
+
+TEST(ReadSeedMaterialFromOSEntropy, ReadZeroBytesIsNoOp) {
+ uint32_t seed_material[32] = {};
+ std::memset(seed_material, 0xAA, sizeof(seed_material));
+ EXPECT_TRUE(absl::random_internal::ReadSeedMaterialFromOSEntropy(
+ absl::Span<uint32_t>(seed_material, 0)));
+
+ EXPECT_THAT(seed_material, Each(Eq(0xAAAAAAAA)));
+}
+
+TEST(ReadSeedMaterialFromOSEntropy, NullPtrVectorArgument) {
+#ifdef NDEBUG
+ EXPECT_FALSE(absl::random_internal::ReadSeedMaterialFromOSEntropy(
+ absl::Span<uint32_t>(nullptr, 32)));
+#else
+ bool result;
+ ABSL_EXPECT_DEATH_IF_SUPPORTED(
+ result = absl::random_internal::ReadSeedMaterialFromOSEntropy(
+ absl::Span<uint32_t>(nullptr, 32)),
+ "!= nullptr");
+ (void)result; // suppress unused-variable warning
+#endif
+}
+
+TEST(ReadSeedMaterialFromURBG, SeedMaterialEqualsVariateSequence) {
+ // Two default-constructed instances of std::mt19937_64 are guaranteed to
+ // produce equal variate-sequences.
+ std::mt19937 urbg_1;
+ std::mt19937 urbg_2;
+ constexpr size_t kSeedMaterialSize = 1024;
+ uint32_t seed_material[kSeedMaterialSize] = {};
+
+ EXPECT_TRUE(absl::random_internal::ReadSeedMaterialFromURBG(
+ &urbg_1, absl::Span<uint32_t>(seed_material, kSeedMaterialSize)));
+ for (uint32_t seed : seed_material) {
+ EXPECT_EQ(seed, urbg_2());
+ }
+}
+
+TEST(ReadSeedMaterialFromURBG, ReadZeroBytesIsNoOp) {
+ std::mt19937_64 urbg;
+ uint32_t seed_material[32];
+ std::memset(seed_material, 0xAA, sizeof(seed_material));
+ EXPECT_TRUE(absl::random_internal::ReadSeedMaterialFromURBG(
+ &urbg, absl::Span<uint32_t>(seed_material, 0)));
+
+ EXPECT_THAT(seed_material, Each(Eq(0xAAAAAAAA)));
+}
+
+TEST(ReadSeedMaterialFromURBG, NullUrbgArgument) {
+ constexpr size_t kSeedMaterialSize = 32;
+ uint32_t seed_material[kSeedMaterialSize];
+#ifdef NDEBUG
+ EXPECT_FALSE(absl::random_internal::ReadSeedMaterialFromURBG<std::mt19937_64>(
+ nullptr, absl::Span<uint32_t>(seed_material, kSeedMaterialSize)));
+#else
+ bool result;
+ ABSL_EXPECT_DEATH_IF_SUPPORTED(
+ result = absl::random_internal::ReadSeedMaterialFromURBG<std::mt19937_64>(
+ nullptr, absl::Span<uint32_t>(seed_material, kSeedMaterialSize)),
+ "!= nullptr");
+ (void)result; // suppress unused-variable warning
+#endif
+}
+
+TEST(ReadSeedMaterialFromURBG, NullPtrVectorArgument) {
+ std::mt19937_64 urbg;
+#ifdef NDEBUG
+ EXPECT_FALSE(absl::random_internal::ReadSeedMaterialFromURBG(
+ &urbg, absl::Span<uint32_t>(nullptr, 32)));
+#else
+ bool result;
+ ABSL_EXPECT_DEATH_IF_SUPPORTED(
+ result = absl::random_internal::ReadSeedMaterialFromURBG(
+ &urbg, absl::Span<uint32_t>(nullptr, 32)),
+ "!= nullptr");
+ (void)result; // suppress unused-variable warning
+#endif
+}
+
+// The avalanche effect is a desirable cryptographic property of hashes in which
+// changing a single bit in the input causes each bit of the output to be
+// changed with probability near 50%.
+//
+// https://en.wikipedia.org/wiki/Avalanche_effect
+
+TEST(MixSequenceIntoSeedMaterial, AvalancheEffectTestOneBitLong) {
+ std::vector<uint32_t> seed_material = {1, 2, 3, 4, 5, 6, 7, 8};
+
+ // For every 32-bit number with exactly one bit set, verify the avalanche
+ // effect holds. In order to reduce flakiness of tests, accept values
+ // anywhere in the range of 30%-70%.
+ for (uint32_t v = 1; v != 0; v <<= 1) {
+ std::vector<uint32_t> seed_material_copy = seed_material;
+ absl::random_internal::MixIntoSeedMaterial(
+ absl::Span<uint32_t>(&v, 1),
+ absl::Span<uint32_t>(seed_material_copy.data(),
+ seed_material_copy.size()));
+
+ uint32_t changed_bits = 0;
+ for (size_t i = 0; i < seed_material.size(); i++) {
+ std::bitset<sizeof(uint32_t) * 8> bitset(seed_material[i] ^
+ seed_material_copy[i]);
+ changed_bits += bitset.count();
+ }
+
+ EXPECT_LE(changed_bits, 0.7 * sizeof(uint32_t) * 8 * seed_material.size());
+ EXPECT_GE(changed_bits, 0.3 * sizeof(uint32_t) * 8 * seed_material.size());
+ }
+}
+
+TEST(MixSequenceIntoSeedMaterial, AvalancheEffectTestOneBitShort) {
+ std::vector<uint32_t> seed_material = {1};
+
+ // For every 32-bit number with exactly one bit set, verify the avalanche
+ // effect holds. In order to reduce flakiness of tests, accept values
+ // anywhere in the range of 30%-70%.
+ for (uint32_t v = 1; v != 0; v <<= 1) {
+ std::vector<uint32_t> seed_material_copy = seed_material;
+ absl::random_internal::MixIntoSeedMaterial(
+ absl::Span<uint32_t>(&v, 1),
+ absl::Span<uint32_t>(seed_material_copy.data(),
+ seed_material_copy.size()));
+
+ uint32_t changed_bits = 0;
+ for (size_t i = 0; i < seed_material.size(); i++) {
+ std::bitset<sizeof(uint32_t) * 8> bitset(seed_material[i] ^
+ seed_material_copy[i]);
+ changed_bits += bitset.count();
+ }
+
+ EXPECT_LE(changed_bits, 0.7 * sizeof(uint32_t) * 8 * seed_material.size());
+ EXPECT_GE(changed_bits, 0.3 * sizeof(uint32_t) * 8 * seed_material.size());
+ }
+}
+
+} // namespace
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-03 01:22:36 +0000