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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
// Copyright (c) 2012 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "util/random.h"
#include <cstring>
#include <vector>
#include "test_util/testharness.h"
using ROCKSDB_NAMESPACE::Random;
TEST(RandomTest, Uniform) {
const int average = 20;
for (uint32_t seed : {0, 1, 2, 37, 4096}) {
Random r(seed);
for (int range : {1, 2, 8, 12, 100}) {
std::vector<int> counts(range, 0);
for (int i = 0; i < range * average; ++i) {
++counts.at(r.Uniform(range));
}
int max_variance = static_cast<int>(std::sqrt(range) * 2 + 4);
for (int i = 0; i < range; ++i) {
EXPECT_GE(counts[i], std::max(1, average - max_variance));
EXPECT_LE(counts[i], average + max_variance + 1);
}
}
}
}
TEST(RandomTest, OneIn) {
Random r(42);
for (int range : {1, 2, 8, 12, 100, 1234}) {
const int average = 100;
int count = 0;
for (int i = 0; i < average * range; ++i) {
if (r.OneIn(range)) {
++count;
}
}
if (range == 1) {
EXPECT_EQ(count, average);
} else {
int max_variance = static_cast<int>(std::sqrt(average) * 1.5);
EXPECT_GE(count, average - max_variance);
EXPECT_LE(count, average + max_variance);
}
}
}
TEST(RandomTest, OneInOpt) {
Random r(42);
for (int range : {-12, 0, 1, 2, 8, 12, 100, 1234}) {
const int average = 100;
int count = 0;
for (int i = 0; i < average * range; ++i) {
if (r.OneInOpt(range)) {
++count;
}
}
if (range < 1) {
EXPECT_EQ(count, 0);
} else if (range == 1) {
EXPECT_EQ(count, average);
} else {
int max_variance = static_cast<int>(std::sqrt(average) * 1.5);
EXPECT_GE(count, average - max_variance);
EXPECT_LE(count, average + max_variance);
}
}
}
TEST(RandomTest, PercentTrue) {
Random r(42);
for (int pct : {-12, 0, 1, 2, 10, 50, 90, 98, 99, 100, 1234}) {
const int samples = 10000;
int count = 0;
for (int i = 0; i < samples; ++i) {
if (r.PercentTrue(pct)) {
++count;
}
}
if (pct <= 0) {
EXPECT_EQ(count, 0);
} else if (pct >= 100) {
EXPECT_EQ(count, samples);
} else {
int est = (count * 100 + (samples / 2)) / samples;
EXPECT_EQ(est, pct);
}
}
}
int main(int argc, char** argv) {
ROCKSDB_NAMESPACE::port::InstallStackTraceHandler();
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
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