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| // Copyright 2016 Google Inc. All rights reserved.
| //
| // 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
| //
| // http://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 "src/weighted_reservoir_sampler.h"
|
| #include <tuple>
| #include <vector>
|
| #include "port/gtest.h"
|
| using testing::TestWithParam;
| using testing::ValuesIn;
| using testing::Combine;
| using testing::Range;
|
| namespace protobuf_mutator {
|
| class WeightedReservoirSamplerTest
| : public TestWithParam<std::tuple<int, std::vector<int>>> {};
|
| const int kRuns = 1000000;
|
| const std::vector<int> kTests[] = {
| {1},
| {1, 1, 1},
| {1, 1, 0},
| {1, 10, 100},
| {100, 1, 10},
| {1, 10000, 10000},
| {1, 3, 7, 100, 105},
| {93519, 52999, 354, 37837, 55285, 31787, 89096, 55695, 1587,
| 18233, 77557, 67632, 59348, 51250, 17417, 96856, 78568, 44296,
| 70170, 41328, 9206, 90187, 54086, 35602, 53167, 33791, 60118,
| 52962, 10327, 80513, 49526, 18326, 83662, 49644, 70903, 4910,
| 36309, 19196, 42982, 53316, 14773, 86607, 60835}};
|
| INSTANTIATE_TEST_CASE_P(AllTest, WeightedReservoirSamplerTest,
| Combine(Range(1, 10, 3), ValuesIn(kTests)));
|
| TEST_P(WeightedReservoirSamplerTest, Test) {
| std::vector<int> weights = std::get<1>(GetParam());
| std::vector<int> counts(weights.size(), 0);
|
| using RandomEngine = std::mt19937;
| RandomEngine rand(std::get<0>(GetParam()));
| for (int i = 0; i < kRuns; ++i) {
| WeightedReservoirSampler<int, RandomEngine> sampler(&rand);
| for (size_t j = 0; j < weights.size(); ++j) sampler.Try(weights[j], j);
| ++counts[sampler.selected()];
| }
|
| int sum = std::accumulate(weights.begin(), weights.end(), 0);
| for (size_t j = 0; j < weights.size(); ++j) {
| float expected = weights[j];
| expected /= sum;
|
| float actual = counts[j];
| actual /= kRuns;
|
| EXPECT_NEAR(expected, actual, 0.01);
| }
| }
|
| } // namespace protobuf_mutator
|
|
