1 files changed, 347 insertions, 0 deletions
diff --git a/absl/random/mocking_bit_gen_test.cc b/absl/random/mocking_bit_gen_test.cc
new file mode 100644
index 000000000000..dcf74fd6db85
--- /dev/null
+++ b/absl/random/mocking_bit_gen_test.cc
@@ -0,0 +1,347 @@
+//
+// 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/mocking_bit_gen.h"
+
+#include <numeric>
+#include <random>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest-spi.h"
+#include "gtest/gtest.h"
+#include "absl/random/bit_gen_ref.h"
+#include "absl/random/mock_distributions.h"
+#include "absl/random/random.h"
+
+namespace {
+using ::testing::Ne;
+using ::testing::Return;
+
+TEST(BasicMocking, AllDistributionsAreOverridable) {
+  absl::MockingBitGen gen;
+
+  EXPECT_NE(absl::Uniform<int>(gen, 1, 1000000), 20);
+  EXPECT_CALL(absl::MockUniform<int>(), Call(gen, 1, 1000000))
+      .WillOnce(Return(20));
+  EXPECT_EQ(absl::Uniform<int>(gen, 1, 1000000), 20);
+
+  EXPECT_NE(absl::Uniform<double>(gen, 0.0, 100.0), 5.0);
+  EXPECT_CALL(absl::MockUniform<double>(), Call(gen, 0.0, 100.0))
+      .WillOnce(Return(5.0));
+  EXPECT_EQ(absl::Uniform<double>(gen, 0.0, 100.0), 5.0);
+
+  EXPECT_NE(absl::Exponential<double>(gen, 1.0), 42);
+  EXPECT_CALL(absl::MockExponential<double>(), Call(gen, 1.0))
+      .WillOnce(Return(42));
+  EXPECT_EQ(absl::Exponential<double>(gen, 1.0), 42);
+
+  EXPECT_NE(absl::Poisson<int>(gen, 1.0), 500);
+  EXPECT_CALL(absl::MockPoisson<int>(), Call(gen, 1.0)).WillOnce(Return(500));
+  EXPECT_EQ(absl::Poisson<int>(gen, 1.0), 500);
+
+  EXPECT_NE(absl::Bernoulli(gen, 0.000001), true);
+  EXPECT_CALL(absl::MockBernoulli(), Call(gen, 0.000001))
+      .WillOnce(Return(true));
+  EXPECT_EQ(absl::Bernoulli(gen, 0.000001), true);
+
+  EXPECT_NE(absl::Zipf<int>(gen, 1000000, 2.0, 1.0), 1221);
+  EXPECT_CALL(absl::MockZipf<int>(), Call(gen, 1000000, 2.0, 1.0))
+      .WillOnce(Return(1221));
+  EXPECT_EQ(absl::Zipf<int>(gen, 1000000, 2.0, 1.0), 1221);
+
+  EXPECT_NE(absl::Gaussian<double>(gen, 0.0, 1.0), 0.001);
+  EXPECT_CALL(absl::MockGaussian<double>(), Call(gen, 0.0, 1.0))
+      .WillOnce(Return(0.001));
+  EXPECT_EQ(absl::Gaussian<double>(gen, 0.0, 1.0), 0.001);
+
+  EXPECT_NE(absl::LogUniform<int>(gen, 0, 1000000, 2), 2040);
+  EXPECT_CALL(absl::MockLogUniform<int>(), Call(gen, 0, 1000000, 2))
+      .WillOnce(Return(2040));
+  EXPECT_EQ(absl::LogUniform<int>(gen, 0, 1000000, 2), 2040);
+}
+
+TEST(BasicMocking, OnDistribution) {
+  absl::MockingBitGen gen;
+
+  EXPECT_NE(absl::Uniform<int>(gen, 1, 1000000), 20);
+  ON_CALL(absl::MockUniform<int>(), Call(gen, 1, 1000000))
+      .WillByDefault(Return(20));
+  EXPECT_EQ(absl::Uniform<int>(gen, 1, 1000000), 20);
+
+  EXPECT_NE(absl::Uniform<double>(gen, 0.0, 100.0), 5.0);
+  ON_CALL(absl::MockUniform<double>(), Call(gen, 0.0, 100.0))
+      .WillByDefault(Return(5.0));
+  EXPECT_EQ(absl::Uniform<double>(gen, 0.0, 100.0), 5.0);
+
+  EXPECT_NE(absl::Exponential<double>(gen, 1.0), 42);
+  ON_CALL(absl::MockExponential<double>(), Call(gen, 1.0))
+      .WillByDefault(Return(42));
+  EXPECT_EQ(absl::Exponential<double>(gen, 1.0), 42);
+
+  EXPECT_NE(absl::Poisson<int>(gen, 1.0), 500);
+  ON_CALL(absl::MockPoisson<int>(), Call(gen, 1.0)).WillByDefault(Return(500));
+  EXPECT_EQ(absl::Poisson<int>(gen, 1.0), 500);
+
+  EXPECT_NE(absl::Bernoulli(gen, 0.000001), true);
+  ON_CALL(absl::MockBernoulli(), Call(gen, 0.000001))
+      .WillByDefault(Return(true));
+  EXPECT_EQ(absl::Bernoulli(gen, 0.000001), true);
+
+  EXPECT_NE(absl::Zipf<int>(gen, 1000000, 2.0, 1.0), 1221);
+  ON_CALL(absl::MockZipf<int>(), Call(gen, 1000000, 2.0, 1.0))
+      .WillByDefault(Return(1221));
+  EXPECT_EQ(absl::Zipf<int>(gen, 1000000, 2.0, 1.0), 1221);
+
+  EXPECT_NE(absl::Gaussian<double>(gen, 0.0, 1.0), 0.001);
+  ON_CALL(absl::MockGaussian<double>(), Call(gen, 0.0, 1.0))
+      .WillByDefault(Return(0.001));
+  EXPECT_EQ(absl::Gaussian<double>(gen, 0.0, 1.0), 0.001);
+
+  EXPECT_NE(absl::LogUniform<int>(gen, 0, 1000000, 2), 2040);
+  ON_CALL(absl::MockLogUniform<int>(), Call(gen, 0, 1000000, 2))
+      .WillByDefault(Return(2040));
+  EXPECT_EQ(absl::LogUniform<int>(gen, 0, 1000000, 2), 2040);
+}
+
+TEST(BasicMocking, GMockMatchers) {
+  absl::MockingBitGen gen;
+
+  EXPECT_NE(absl::Zipf<int>(gen, 1000000, 2.0, 1.0), 1221);
+  ON_CALL(absl::MockZipf<int>(), Call(gen, 1000000, 2.0, 1.0))
+      .WillByDefault(Return(1221));
+  EXPECT_EQ(absl::Zipf<int>(gen, 1000000, 2.0, 1.0), 1221);
+}
+
+TEST(BasicMocking, OverridesWithMultipleGMockExpectations) {
+  absl::MockingBitGen gen;
+
+  EXPECT_CALL(absl::MockUniform<int>(), Call(gen, 1, 10000))
+      .WillOnce(Return(20))
+      .WillOnce(Return(40))
+      .WillOnce(Return(60));
+  EXPECT_EQ(absl::Uniform(gen, 1, 10000), 20);
+  EXPECT_EQ(absl::Uniform(gen, 1, 10000), 40);
+  EXPECT_EQ(absl::Uniform(gen, 1, 10000), 60);
+}
+
+TEST(BasicMocking, DefaultArgument) {
+  absl::MockingBitGen gen;
+
+  ON_CALL(absl::MockExponential<double>(), Call(gen, 1.0))
+      .WillByDefault(Return(200));
+
+  EXPECT_EQ(absl::Exponential<double>(gen), 200);
+  EXPECT_EQ(absl::Exponential<double>(gen, 1.0), 200);
+}
+
+TEST(BasicMocking, MultipleGenerators) {
+  auto get_value = [](absl::BitGenRef gen_ref) {
+    return absl::Uniform(gen_ref, 1, 1000000);
+  };
+  absl::MockingBitGen unmocked_generator;
+  absl::MockingBitGen mocked_with_3;
+  absl::MockingBitGen mocked_with_11;
+
+  EXPECT_CALL(absl::MockUniform<int>(), Call(mocked_with_3, 1, 1000000))
+      .WillOnce(Return(3))
+      .WillRepeatedly(Return(17));
+  EXPECT_CALL(absl::MockUniform<int>(), Call(mocked_with_11, 1, 1000000))
+      .WillOnce(Return(11))
+      .WillRepeatedly(Return(17));
+
+  // Ensure that unmocked generator generates neither value.
+  int unmocked_value = get_value(unmocked_generator);
+  EXPECT_NE(unmocked_value, 3);
+  EXPECT_NE(unmocked_value, 11);
+  // Mocked generators should generate their mocked values.
+  EXPECT_EQ(get_value(mocked_with_3), 3);
+  EXPECT_EQ(get_value(mocked_with_11), 11);
+  // Ensure that the mocks have expired.
+  EXPECT_NE(get_value(mocked_with_3), 3);
+  EXPECT_NE(get_value(mocked_with_11), 11);
+}
+
+TEST(BasicMocking, MocksNotTrigeredForIncorrectTypes) {
+  absl::MockingBitGen gen;
+  EXPECT_CALL(absl::MockUniform<uint32_t>(), Call(gen)).WillOnce(Return(42));
+
+  EXPECT_NE(absl::Uniform<uint16_t>(gen), 42);  // Not mocked
+  EXPECT_EQ(absl::Uniform<uint32_t>(gen), 42);  // Mock triggered
+}
+
+TEST(BasicMocking, FailsOnUnsatisfiedMocks) {
+  EXPECT_NONFATAL_FAILURE(
+      []() {
+        absl::MockingBitGen gen;
+        EXPECT_CALL(absl::MockExponential<double>(), Call(gen, 1.0))
+            .WillOnce(Return(3.0));
+        // Does not call absl::Exponential().
+      }(),
+      "unsatisfied and active");
+}
+
+TEST(OnUniform, RespectsUniformIntervalSemantics) {
+  absl::MockingBitGen gen;
+
+  EXPECT_CALL(absl::MockUniform<int>(),
+              Call(absl::IntervalClosed, gen, 1, 1000000))
+      .WillOnce(Return(301));
+  EXPECT_NE(absl::Uniform(gen, 1, 1000000), 301);  // Not mocked
+  EXPECT_EQ(absl::Uniform(absl::IntervalClosed, gen, 1, 1000000), 301);
+}
+
+TEST(OnUniform, RespectsNoArgUnsignedShorthand) {
+  absl::MockingBitGen gen;
+  EXPECT_CALL(absl::MockUniform<uint32_t>(), Call(gen)).WillOnce(Return(42));
+  EXPECT_EQ(absl::Uniform<uint32_t>(gen), 42);
+}
+
+TEST(RepeatedlyModifier, ForceSnakeEyesForManyDice) {
+  auto roll_some_dice = [](absl::BitGenRef gen_ref) {
+    std::vector<int> results(16);
+    for (auto& r : results) {
+      r = absl::Uniform(absl::IntervalClosed, gen_ref, 1, 6);
+    }
+    return results;
+  };
+  std::vector<int> results;
+  absl::MockingBitGen gen;
+
+  // Without any mocked calls, not all dice roll a "6".
+  results = roll_some_dice(gen);
+  EXPECT_LT(std::accumulate(std::begin(results), std::end(results), 0),
+            results.size() * 6);
+
+  // Verify that we can force all "6"-rolls, with mocking.
+  ON_CALL(absl::MockUniform<int>(), Call(absl::IntervalClosed, gen, 1, 6))
+      .WillByDefault(Return(6));
+  results = roll_some_dice(gen);
+  EXPECT_EQ(std::accumulate(std::begin(results), std::end(results), 0),
+            results.size() * 6);
+}
+
+TEST(WillOnce, DistinctCounters) {
+  absl::MockingBitGen gen;
+  EXPECT_CALL(absl::MockUniform<int>(), Call(gen, 1, 1000000))
+      .Times(3)
+      .WillRepeatedly(Return(0));
+  EXPECT_CALL(absl::MockUniform<int>(), Call(gen, 1000001, 2000000))
+      .Times(3)
+      .WillRepeatedly(Return(1));
+  EXPECT_EQ(absl::Uniform(gen, 1000001, 2000000), 1);
+  EXPECT_EQ(absl::Uniform(gen, 1, 1000000), 0);
+  EXPECT_EQ(absl::Uniform(gen, 1000001, 2000000), 1);
+  EXPECT_EQ(absl::Uniform(gen, 1, 1000000), 0);
+  EXPECT_EQ(absl::Uniform(gen, 1000001, 2000000), 1);
+  EXPECT_EQ(absl::Uniform(gen, 1, 1000000), 0);
+}
+
+TEST(TimesModifier, ModifierSaturatesAndExpires) {
+  EXPECT_NONFATAL_FAILURE(
+      []() {
+        absl::MockingBitGen gen;
+        EXPECT_CALL(absl::MockUniform<int>(), Call(gen, 1, 1000000))
+            .Times(3)
+            .WillRepeatedly(Return(15))
+            .RetiresOnSaturation();
+
+        EXPECT_EQ(absl::Uniform(gen, 1, 1000000), 15);
+        EXPECT_EQ(absl::Uniform(gen, 1, 1000000), 15);
+        EXPECT_EQ(absl::Uniform(gen, 1, 1000000), 15);
+        // Times(3) has expired - Should get a different value now.
+
+        EXPECT_NE(absl::Uniform(gen, 1, 1000000), 15);
+      }(),
+      "");
+}
+
+TEST(TimesModifier, Times0) {
+  absl::MockingBitGen gen;
+  EXPECT_CALL(absl::MockBernoulli(), Call(gen, 0.0)).Times(0);
+  EXPECT_CALL(absl::MockPoisson<int>(), Call(gen, 1.0)).Times(0);
+}
+
+TEST(AnythingMatcher, MatchesAnyArgument) {
+  using testing::_;
+
+  {
+    absl::MockingBitGen gen;
+    ON_CALL(absl::MockUniform<int>(), Call(absl::IntervalClosed, gen, _, 1000))
+        .WillByDefault(Return(11));
+    ON_CALL(absl::MockUniform<int>(),
+            Call(absl::IntervalClosed, gen, _, Ne(1000)))
+        .WillByDefault(Return(99));
+
+    EXPECT_EQ(absl::Uniform(absl::IntervalClosed, gen, 10, 1000000), 99);
+    EXPECT_EQ(absl::Uniform(absl::IntervalClosed, gen, 10, 1000), 11);
+  }
+
+  {
+    absl::MockingBitGen gen;
+    ON_CALL(absl::MockUniform<int>(), Call(gen, 1, _))
+        .WillByDefault(Return(25));
+    ON_CALL(absl::MockUniform<int>(), Call(gen, Ne(1), _))
+        .WillByDefault(Return(99));
+    EXPECT_EQ(absl::Uniform(gen, 3, 1000000), 99);
+    EXPECT_EQ(absl::Uniform(gen, 1, 1000000), 25);
+  }
+
+  {
+    absl::MockingBitGen gen;
+    ON_CALL(absl::MockUniform<int>(), Call(gen, _, _))
+        .WillByDefault(Return(145));
+    EXPECT_EQ(absl::Uniform(gen, 1, 1000), 145);
+    EXPECT_EQ(absl::Uniform(gen, 10, 1000), 145);
+    EXPECT_EQ(absl::Uniform(gen, 100, 1000), 145);
+  }
+}
+
+TEST(AnythingMatcher, WithWillByDefault) {
+  using testing::_;
+  absl::MockingBitGen gen;
+  std::vector<int> values = {11, 22, 33, 44, 55, 66, 77, 88, 99, 1010};
+
+  ON_CALL(absl::MockUniform<size_t>(), Call(gen, 0, _))
+      .WillByDefault(Return(0));
+  for (int i = 0; i < 100; i++) {
+    auto& elem = values[absl::Uniform(gen, 0u, values.size())];
+    EXPECT_EQ(elem, 11);
+  }
+}
+
+TEST(BasicMocking, WillByDefaultWithArgs) {
+  using testing::_;
+
+  absl::MockingBitGen gen;
+  ON_CALL(absl::MockPoisson<int>(), Call(gen, _))
+      .WillByDefault(
+          [](double lambda) { return static_cast<int>(lambda * 10); });
+  EXPECT_EQ(absl::Poisson<int>(gen, 1.7), 17);
+  EXPECT_EQ(absl::Poisson<int>(gen, 0.03), 0);
+}
+
+TEST(MockingBitGen, InSequenceSucceedsInOrder) {
+  absl::MockingBitGen gen;
+
+  testing::InSequence seq;
+
+  EXPECT_CALL(absl::MockPoisson<int>(), Call(gen, 1.0)).WillOnce(Return(3));
+  EXPECT_CALL(absl::MockPoisson<int>(), Call(gen, 2.0)).WillOnce(Return(4));
+
+  EXPECT_EQ(absl::Poisson<int>(gen, 1.0), 3);
+  EXPECT_EQ(absl::Poisson<int>(gen, 2.0), 4);
+}
+
+}  // namespace