1 files changed, 40 insertions, 9 deletions

diff --git a/third_party/abseil-cpp/absl/random/internal/explicit_seed_seq_test.cc b/third_party/abseil-cpp/absl/random/internal/explicit_seed_seq_test.cc
index a55ad73948..f867f610d0 100644
--- a/third_party/abseil-cpp/absl/random/internal/explicit_seed_seq_test.cc
+++ b/third_party/abseil-cpp/absl/random/internal/explicit_seed_seq_test.cc
@@ -24,6 +24,8 @@
 
 namespace {
 
+using ::absl::random_internal::ExplicitSeedSeq;
+
 template <typename Sseq>
 bool ConformsToInterface() {
   // Check that the SeedSequence can be default-constructed.
@@ -64,14 +66,14 @@ TEST(SeedSequences, CheckInterfaces) {
   EXPECT_TRUE(ConformsToInterface<std::seed_seq>());
 
   // Abseil classes
-  EXPECT_TRUE(ConformsToInterface<absl::random_internal::ExplicitSeedSeq>());
+  EXPECT_TRUE(ConformsToInterface<ExplicitSeedSeq>());
 }
 
 TEST(ExplicitSeedSeq, DefaultConstructorGeneratesZeros) {
   const size_t kNumBlocks = 128;
 
   uint32_t outputs[kNumBlocks];
-  absl::random_internal::ExplicitSeedSeq seq;
+  ExplicitSeedSeq seq;
   seq.generate(outputs, &outputs[kNumBlocks]);
 
   for (uint32_t& seed : outputs) {
@@ -87,8 +89,7 @@ TEST(ExplicitSeeqSeq, SeedMaterialIsForwardedIdentically) {
   for (uint32_t& seed : seed_material) {
     seed = urandom();
   }
-  absl::random_internal::ExplicitSeedSeq seq(seed_material,
-                                             &seed_material[kNumBlocks]);
+  ExplicitSeedSeq seq(seed_material, &seed_material[kNumBlocks]);
 
   // Check that output is same as seed-material provided to constructor.
   {
@@ -133,11 +134,10 @@ TEST(ExplicitSeedSeq, CopyAndMoveConstructors) {
   for (uint32_t& entry : entropy) {
     entry = urandom();
   }
-  absl::random_internal::ExplicitSeedSeq seq_from_entropy(std::begin(entropy),
-                                                          std::end(entropy));
+  ExplicitSeedSeq seq_from_entropy(std::begin(entropy), std::end(entropy));
   // Copy constructor.
   {
-    absl::random_internal::ExplicitSeedSeq seq_copy(seq_from_entropy);
+    ExplicitSeedSeq seq_copy(seq_from_entropy);
     EXPECT_EQ(seq_copy.size(), seq_from_entropy.size());
 
     std::vector<uint32_t> seeds_1;
@@ -155,8 +155,7 @@ TEST(ExplicitSeedSeq, CopyAndMoveConstructors) {
     for (uint32_t& entry : entropy) {
       entry = urandom();
     }
-    absl::random_internal::ExplicitSeedSeq another_seq(std::begin(entropy),
-                                                       std::end(entropy));
+    ExplicitSeedSeq another_seq(std::begin(entropy), std::end(entropy));
 
     std::vector<uint32_t> seeds_1;
     seeds_1.resize(1000, 0);
@@ -202,3 +201,35 @@ TEST(ExplicitSeedSeq, CopyAndMoveConstructors) {
     EXPECT_THAT(seeds_1, Each(Eq(0)));
   }
 }
+
+TEST(ExplicitSeedSeq, StdURBGGoldenTests) {
+  // Verify that for std::- URBG instances the results are stable across
+  // platforms (these should have deterministic output).
+  {
+    ExplicitSeedSeq seed_sequence{12, 34, 56};
+    std::minstd_rand rng(seed_sequence);
+
+    std::minstd_rand::result_type values[4] = {rng(), rng(), rng(), rng()};
+    EXPECT_THAT(values,
+                testing::ElementsAre(579252, 43785881, 464353103, 1501811174));
+  }
+
+  {
+    ExplicitSeedSeq seed_sequence{12, 34, 56};
+    std::mt19937 rng(seed_sequence);
+
+    std::mt19937::result_type values[4] = {rng(), rng(), rng(), rng()};
+    EXPECT_THAT(values, testing::ElementsAre(138416803, 151130212, 33817739,
+                                             138416803));
+  }
+
+  {
+    ExplicitSeedSeq seed_sequence{12, 34, 56};
+    std::mt19937_64 rng(seed_sequence);
+
+    std::mt19937_64::result_type values[4] = {rng(), rng(), rng(), rng()};
+    EXPECT_THAT(values,
+                testing::ElementsAre(19738651785169348, 1464811352364190456,
+                                     18054685302720800, 19738651785169348));
+  }
+}