Export of internal Abseil changes

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4503a1945d61540d3f7dd9ee2399297fbd423b82 by Andy Soffer <asoffer@google.com>:

Releasing absl::MockingBitGen and absl::BitGenRef

PiperOrigin-RevId: 281594380

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2cb926fd9e39b5fa24c9541bfafcf18916cf7df2 by Abseil Team <absl-team@google.com>:

Explicitly export files needed by other packages

PiperOrigin-RevId: 281482304
GitOrigin-RevId: 4503a1945d61540d3f7dd9ee2399297fbd423b82
Change-Id: Id9f694eaaa23f42de817c8e8a28e6f86444f5637

absl/random/bit_gen_ref_test.cc

@@ -0,0 +1,99 @@
+//
+// Copyright 2018 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/bit_gen_ref.h"
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "absl/random/internal/sequence_urbg.h"
+#include "absl/random/random.h"
+
+namespace absl {
+
+class ConstBitGen : public absl::random_internal::MockingBitGenBase {
+  bool CallImpl(const std::type_info&, void*, void* result) override {
+    *static_cast<int*>(result) = 42;
+    return true;
+  }
+};
+
+namespace random_internal {
+template <>
+struct DistributionCaller<ConstBitGen> {
+  template <typename DistrT, typename FormatT, typename... Args>
+  static typename DistrT::result_type Call(ConstBitGen* gen, Args&&... args) {
+    return gen->template Call<DistrT, FormatT>(std::forward<Args>(args)...);
+  }
+};
+}  // namespace random_internal
+
+namespace {
+int FnTest(absl::BitGenRef gen_ref) { return absl::Uniform(gen_ref, 1, 7); }
+
+template <typename T>
+class BitGenRefTest : public testing::Test {};
+
+using BitGenTypes =
+    ::testing::Types<absl::BitGen, absl::InsecureBitGen, std::mt19937,
+                     std::mt19937_64, std::minstd_rand>;
+TYPED_TEST_SUITE(BitGenRefTest, BitGenTypes);
+
+TYPED_TEST(BitGenRefTest, BasicTest) {
+  TypeParam gen;
+  auto x = FnTest(gen);
+  EXPECT_NEAR(x, 4, 3);
+}
+
+TYPED_TEST(BitGenRefTest, Copyable) {
+  TypeParam gen;
+  absl::BitGenRef gen_ref(gen);
+  FnTest(gen_ref);  // Copy
+}
+
+TEST(BitGenRefTest, PassThroughEquivalence) {
+  // sequence_urbg returns 64-bit results.
+  absl::random_internal::sequence_urbg urbg(
+      {0x0003eb76f6f7f755ull, 0xFFCEA50FDB2F953Bull, 0xC332DDEFBE6C5AA5ull,
+       0x6558218568AB9702ull, 0x2AEF7DAD5B6E2F84ull, 0x1521B62829076170ull,
+       0xECDD4775619F1510ull, 0x13CCA830EB61BD96ull, 0x0334FE1EAA0363CFull,
+       0xB5735C904C70A239ull, 0xD59E9E0BCBAADE14ull, 0xEECC86BC60622CA7ull});
+
+  std::vector<uint64_t> output(12);
+
+  {
+    absl::BitGenRef view(urbg);
+    for (auto& v : output) {
+      v = view();
+    }
+  }
+
+  std::vector<uint64_t> expected(
+      {0x0003eb76f6f7f755ull, 0xFFCEA50FDB2F953Bull, 0xC332DDEFBE6C5AA5ull,
+       0x6558218568AB9702ull, 0x2AEF7DAD5B6E2F84ull, 0x1521B62829076170ull,
+       0xECDD4775619F1510ull, 0x13CCA830EB61BD96ull, 0x0334FE1EAA0363CFull,
+       0xB5735C904C70A239ull, 0xD59E9E0BCBAADE14ull, 0xEECC86BC60622CA7ull});
+
+  EXPECT_THAT(output, testing::Eq(expected));
+}
+
+TEST(BitGenRefTest, MockingBitGenBaseOverrides) {
+  ConstBitGen const_gen;
+  EXPECT_EQ(FnTest(const_gen), 42);
+
+  absl::BitGenRef gen_ref(const_gen);
+  EXPECT_EQ(FnTest(gen_ref), 42);  // Copy
+}
+}  // namespace
+}  // namespace absl