1 files changed, 245 insertions, 0 deletions
diff --git a/third_party/abseil_cpp/absl/random/internal/nonsecure_base_test.cc b/third_party/abseil_cpp/absl/random/internal/nonsecure_base_test.cc
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+++ b/third_party/abseil_cpp/absl/random/internal/nonsecure_base_test.cc
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+// 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/nonsecure_base.h"
+
+#include <algorithm>
+#include <iostream>
+#include <memory>
+#include <random>
+#include <sstream>
+
+#include "gtest/gtest.h"
+#include "absl/random/distributions.h"
+#include "absl/random/random.h"
+#include "absl/strings/str_cat.h"
+
+namespace {
+
+using ExampleNonsecureURBG =
+    absl::random_internal::NonsecureURBGBase<std::mt19937>;
+
+template <typename T>
+void Use(const T&) {}
+
+}  // namespace
+
+TEST(NonsecureURBGBase, DefaultConstructorIsValid) {
+  ExampleNonsecureURBG urbg;
+}
+
+// Ensure that the recommended template-instantiations are valid.
+TEST(RecommendedTemplates, CanBeConstructed) {
+  absl::BitGen default_generator;
+  absl::InsecureBitGen insecure_generator;
+}
+
+TEST(RecommendedTemplates, CanDiscardValues) {
+  absl::BitGen default_generator;
+  absl::InsecureBitGen insecure_generator;
+
+  default_generator.discard(5);
+  insecure_generator.discard(5);
+}
+
+TEST(NonsecureURBGBase, StandardInterface) {
+  // Names after definition of [rand.req.urbg] in C++ standard.
+  // e us a value of E
+  // v is a lvalue of E
+  // x, y are possibly const values of E
+  // s is a value of T
+  // q is a value satisfying requirements of seed_sequence
+  // z is a value of type unsigned long long
+  // os is a some specialization of basic_ostream
+  // is is a some specialization of basic_istream
+
+  using E = absl::random_internal::NonsecureURBGBase<std::minstd_rand>;
+
+  using T = typename E::result_type;
+
+  static_assert(!std::is_copy_constructible<E>::value,
+                "NonsecureURBGBase should not be copy constructible");
+
+  static_assert(!absl::is_copy_assignable<E>::value,
+                "NonsecureURBGBase should not be copy assignable");
+
+  static_assert(std::is_move_constructible<E>::value,
+                "NonsecureURBGBase should be move constructible");
+
+  static_assert(absl::is_move_assignable<E>::value,
+                "NonsecureURBGBase should be move assignable");
+
+  static_assert(std::is_same<decltype(std::declval<E>()()), T>::value,
+                "return type of operator() must be result_type");
+
+  {
+    const E x, y;
+    Use(x);
+    Use(y);
+
+    static_assert(std::is_same<decltype(x == y), bool>::value,
+                  "return type of operator== must be bool");
+
+    static_assert(std::is_same<decltype(x != y), bool>::value,
+                  "return type of operator== must be bool");
+  }
+
+  E e;
+  std::seed_seq q{1, 2, 3};
+
+  E{};
+  E{q};
+
+  // Copy constructor not supported.
+  // E{x};
+
+  // result_type seed constructor not supported.
+  // E{T{1}};
+
+  // Move constructors are supported.
+  {
+    E tmp(q);
+    E m = std::move(tmp);
+    E n(std::move(m));
+    EXPECT_TRUE(e != n);
+  }
+
+  // Comparisons work.
+  {
+    // MSVC emits error 2718 when using EXPECT_EQ(e, x)
+    //  * actual parameter with __declspec(align('#')) won't be aligned
+    E a(q);
+    E b(q);
+
+    EXPECT_TRUE(a != e);
+    EXPECT_TRUE(a == b);
+
+    a();
+    EXPECT_TRUE(a != b);
+  }
+
+  // e.seed(s) not supported.
+
+  // [rand.req.eng] specifies the parameter as 'unsigned long long'
+  // e.discard(unsigned long long) is supported.
+  unsigned long long z = 1;  // NOLINT(runtime/int)
+  e.discard(z);
+}
+
+TEST(NonsecureURBGBase, SeedSeqConstructorIsValid) {
+  std::seed_seq seq;
+  ExampleNonsecureURBG rbg(seq);
+}
+
+TEST(NonsecureURBGBase, CompatibleWithDistributionUtils) {
+  ExampleNonsecureURBG rbg;
+
+  absl::Uniform(rbg, 0, 100);
+  absl::Uniform(rbg, 0.5, 0.7);
+  absl::Poisson<uint32_t>(rbg);
+  absl::Exponential<float>(rbg);
+}
+
+TEST(NonsecureURBGBase, CompatibleWithStdDistributions) {
+  ExampleNonsecureURBG rbg;
+
+  // Cast to void to suppress [[nodiscard]] warnings
+  static_cast<void>(std::uniform_int_distribution<uint32_t>(0, 100)(rbg));
+  static_cast<void>(std::uniform_real_distribution<float>()(rbg));
+  static_cast<void>(std::bernoulli_distribution(0.2)(rbg));
+}
+
+TEST(NonsecureURBGBase, ConsecutiveDefaultInstancesYieldUniqueVariates) {
+  const size_t kNumSamples = 128;
+
+  ExampleNonsecureURBG rbg1;
+  ExampleNonsecureURBG rbg2;
+
+  for (size_t i = 0; i < kNumSamples; i++) {
+    EXPECT_NE(rbg1(), rbg2());
+  }
+}
+
+TEST(NonsecureURBGBase, EqualSeedSequencesYieldEqualVariates) {
+  std::seed_seq seq;
+
+  ExampleNonsecureURBG rbg1(seq);
+  ExampleNonsecureURBG rbg2(seq);
+
+  // ExampleNonsecureURBG rbg3({1, 2, 3});  // Should not compile.
+
+  for (uint32_t i = 0; i < 1000; i++) {
+    EXPECT_EQ(rbg1(), rbg2());
+  }
+
+  rbg1.discard(100);
+  rbg2.discard(100);
+
+  // The sequences should continue after discarding
+  for (uint32_t i = 0; i < 1000; i++) {
+    EXPECT_EQ(rbg1(), rbg2());
+  }
+}
+
+// This is a PRNG-compatible type specifically designed to test
+// that NonsecureURBGBase::Seeder can correctly handle iterators
+// to arbitrary non-uint32_t size types.
+template <typename T>
+struct SeederTestEngine {
+  using result_type = T;
+
+  static constexpr result_type(min)() {
+    return (std::numeric_limits<result_type>::min)();
+  }
+  static constexpr result_type(max)() {
+    return (std::numeric_limits<result_type>::max)();
+  }
+
+  template <class SeedSequence,
+            typename = typename absl::enable_if_t<
+                !std::is_same<SeedSequence, SeederTestEngine>::value>>
+  explicit SeederTestEngine(SeedSequence&& seq) {
+    seed(seq);
+  }
+
+  SeederTestEngine(const SeederTestEngine&) = default;
+  SeederTestEngine& operator=(const SeederTestEngine&) = default;
+  SeederTestEngine(SeederTestEngine&&) = default;
+  SeederTestEngine& operator=(SeederTestEngine&&) = default;
+
+  result_type operator()() { return state[0]; }
+
+  template <class SeedSequence>
+  void seed(SeedSequence&& seq) {
+    std::fill(std::begin(state), std::end(state), T(0));
+    seq.generate(std::begin(state), std::end(state));
+  }
+
+  T state[2];
+};
+
+TEST(NonsecureURBGBase, SeederWorksForU32) {
+  using U32 =
+      absl::random_internal::NonsecureURBGBase<SeederTestEngine<uint32_t>>;
+  U32 x;
+  EXPECT_NE(0, x());
+}
+
+TEST(NonsecureURBGBase, SeederWorksForU64) {
+  using U64 =
+      absl::random_internal::NonsecureURBGBase<SeederTestEngine<uint64_t>>;
+
+  U64 x;
+  EXPECT_NE(0, x());
+}