summaryrefslogtreecommitdiffstats
path: root/src/rocksdb/util/heap_test.cc
blob: d036a62ebc10e701e1246c3e8c4b6b13544d0f5f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
//  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).

#include <gtest/gtest.h>

#include <climits>

#include <queue>
#include <random>
#include <utility>

#include "util/heap.h"

#ifndef GFLAGS
const int64_t FLAGS_iters = 100000;
#else
#include "util/gflags_compat.h"
DEFINE_int64(iters, 100000, "number of pseudo-random operations in each test");
#endif  // GFLAGS

/*
 * Compares the custom heap implementation in util/heap.h against
 * std::priority_queue on a pseudo-random sequence of operations.
 */

namespace rocksdb {

using HeapTestValue = uint64_t;
using Params = std::tuple<size_t, HeapTestValue, int64_t>;

class HeapTest : public ::testing::TestWithParam<Params> {
};

TEST_P(HeapTest, Test) {
  // This test performs the same pseudorandom sequence of operations on a
  // BinaryHeap and an std::priority_queue, comparing output.  The three
  // possible operations are insert, replace top and pop.
  //
  // Insert is chosen slightly more often than the others so that the size of
  // the heap slowly grows.  Once the size heats the MAX_HEAP_SIZE limit, we
  // disallow inserting until the heap becomes empty, testing the "draining"
  // scenario.

  const auto MAX_HEAP_SIZE = std::get<0>(GetParam());
  const auto MAX_VALUE = std::get<1>(GetParam());
  const auto RNG_SEED = std::get<2>(GetParam());

  BinaryHeap<HeapTestValue> heap;
  std::priority_queue<HeapTestValue> ref;

  std::mt19937 rng(static_cast<unsigned int>(RNG_SEED));
  std::uniform_int_distribution<HeapTestValue> value_dist(0, MAX_VALUE);
  int ndrains = 0;
  bool draining = false;     // hit max size, draining until we empty the heap
  size_t size = 0;
  for (int64_t i = 0; i < FLAGS_iters; ++i) {
    if (size == 0) {
      draining = false;
    }

    if (!draining &&
        (size == 0 || std::bernoulli_distribution(0.4)(rng))) {
      // insert
      HeapTestValue val = value_dist(rng);
      heap.push(val);
      ref.push(val);
      ++size;
      if (size == MAX_HEAP_SIZE) {
        draining = true;
        ++ndrains;
      }
    } else if (std::bernoulli_distribution(0.5)(rng)) {
      // replace top
      HeapTestValue val = value_dist(rng);
      heap.replace_top(val);
      ref.pop();
      ref.push(val);
    } else {
      // pop
      assert(size > 0);
      heap.pop();
      ref.pop();
      --size;
    }

    // After every operation, check that the public methods give the same
    // results
    assert((size == 0) == ref.empty());
    ASSERT_EQ(size == 0, heap.empty());
    if (size > 0) {
      ASSERT_EQ(ref.top(), heap.top());
    }
  }

  // Probabilities should be set up to occasionally hit the max heap size and
  // drain it
  assert(ndrains > 0);

  heap.clear();
  ASSERT_TRUE(heap.empty());
}

// Basic test, MAX_VALUE = 3*MAX_HEAP_SIZE (occasional duplicates)
INSTANTIATE_TEST_CASE_P(
  Basic, HeapTest,
  ::testing::Values(Params(1000, 3000, 0x1b575cf05b708945))
);
// Mid-size heap with small values (many duplicates)
INSTANTIATE_TEST_CASE_P(
  SmallValues, HeapTest,
  ::testing::Values(Params(100, 10, 0x5ae213f7bd5dccd0))
);
// Small heap, large value range (no duplicates)
INSTANTIATE_TEST_CASE_P(
  SmallHeap, HeapTest,
  ::testing::Values(Params(10, ULLONG_MAX, 0x3e1fa8f4d01707cf))
);
// Two-element heap
INSTANTIATE_TEST_CASE_P(
  TwoElementHeap, HeapTest,
  ::testing::Values(Params(2, 5, 0x4b5e13ea988c6abc))
);
// One-element heap
INSTANTIATE_TEST_CASE_P(
  OneElementHeap, HeapTest,
  ::testing::Values(Params(1, 3, 0x176a1019ab0b612e))
);

}  // namespace rocksdb

int main(int argc, char** argv) {
  ::testing::InitGoogleTest(&argc, argv);
#ifdef GFLAGS
  GFLAGS_NAMESPACE::ParseCommandLineFlags(&argc, &argv, true);
#endif  // GFLAGS
  return RUN_ALL_TESTS();
}