polardbxengine/unittest/gunit/priority_queue-t.cc

/* Copyright (c) 2014, 2016, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

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   This program is distributed in the hope that it will be useful,
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License, version 2.0, for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

// First include (the generated) my_config.h, to get correct platform defines.
#include <gtest/gtest.h>
#include <algorithm>
#include <functional>
#include <iostream>
#include <iterator>
#include <sstream>
#include <vector>
#include "my_config.h"

#include "priority_queue.h"

namespace priority_queue_unittest {

// random integer generator -- start
template <typename IntegerType>
class random_integer_generator {
 public:
  random_integer_generator(unsigned int seed = 0) { srand(seed); }

  IntegerType operator()(IntegerType const &low, IntegerType const &high) {
    IntegerType i = rand() % (high - low + 1);
    i += low;
    return i;
  }
};
// random integer generator -- end

//--------------------------------------------------------

// handle support -- start
template <typename T>
struct handle {
  T *ptr;

  handle() : ptr(NULL) {}
  handle(T &t) : ptr(&t) {}
};

template <typename T>
inline std::ostream &operator<<(std::ostream &os, handle<T> const &h) {
  os << *h.ptr;
  return os;
}

template <typename Handle, typename Value, typename Less = std::less<Value>>
struct handle_less {
  inline bool operator()(Handle const &p1, Handle const &p2) const {
    return Less()(*p1.ptr, *p2.ptr);
  }
};
// handle support -- end

//--------------------------------------------------------

// dummy stream that "eats" all input
struct null_stream : public std::ostream {
  // Visual Studio needs a default constructor.
  null_stream() : std::ostream(NULL) {}
};

template <typename T>
inline null_stream &operator<<(null_stream &ns, T const &) {
  return ns;
}

//--------------------------------------------------------

// i/o support -- start
template <typename InputIterator>
inline void print_range(std::ostream &os, InputIterator first,
                        InputIterator last) {
  for (InputIterator it = first; it != last; ++it) {
    os << " " << *it;
  }
  os << std::endl;
}

template <typename InputIterator>
inline void print_range(std::ostream &os, std::string const &header,
                        InputIterator first, InputIterator last) {
  os << header;
  print_range(os, first, last);
}
// i/o support -- end

//--------------------------------------------------------

// Some template functions below do not play well with gtest internals
static void assert_true_helper(bool val) { ASSERT_TRUE(val); }

// k min elements algorithm -- start
template <bool UseSorting>
struct min_k_elements {
  template <typename InputIterator, typename OutputIterator>
  static inline OutputIterator apply(InputIterator first, InputIterator last,
                                     size_t k, OutputIterator oit) {
    SCOPED_TRACE("");
    assert_true_helper(static_cast<size_t>(std::distance(first, last)) > k);

    typedef typename std::iterator_traits<InputIterator>::value_type value_type;

    std::vector<value_type> values;

    // copy locally
    std::copy(first, last, std::back_inserter(values));

    // sort
    std::sort(values.begin(), values.end());

    // output k smallest values
    std::copy(values.begin(), values.begin() + k, oit);
    return oit;
  }
};

template <>
struct min_k_elements<false> {
  template <typename RandomAccessIterator, typename OutputIterator>
  static inline OutputIterator apply(RandomAccessIterator first,
                                     RandomAccessIterator last, size_t k,
                                     OutputIterator oit) {
    SCOPED_TRACE("");
    assert_true_helper(static_cast<size_t>(std::distance(first, last)) > k);

    typedef typename std::iterator_traits<RandomAccessIterator>::value_type
        value_type;

    typedef handle<value_type> handle_type;

    typedef handle_less<handle_type, value_type, std::less<value_type>>
        handle_less_type;

    typedef Priority_queue<handle_type, std::vector<handle_type>,
                           handle_less_type>
        queue_type;

    typedef typename queue_type::const_iterator queue_iterator;

    // copy k + 1 values locally
    std::vector<value_type> values;
    values.reserve(k + 1);

    std::copy(first, first + k + 1, std::back_inserter(values));

    // create a queue of k + 1 handles to the local values
    queue_type queue;
    assert_true_helper(!queue.reserve(k + 1));

    for (size_t i = 0; i < k + 1; ++i) {
      EXPECT_FALSE(queue.push(handle_type(values[i])));
    }
    SCOPED_TRACE("");
    assert_true_helper(queue.is_valid());

    // for the remaining values update the queue's root node
    // and rebuild the heap
    for (RandomAccessIterator it = first + k + 1; it != last; ++it) {
      *queue[0].ptr = *it;
      queue.update(0);
    }

    // output the k minimum values (all but the root)
    for (queue_iterator it = ++queue.begin(); it != queue.end(); ++it) {
      *oit++ = *it->ptr;
    }

    return oit;
  }
};
// k min elements algorithm -- end

//--------------------------------------------------------

template <typename RandomAccessIterator>
inline void test_min_k_elements(RandomAccessIterator first,
                                RandomAccessIterator last, size_t k) {
  std::vector<int> keys_copy(first, last);
  std::sort(keys_copy.begin(), keys_copy.end());

#ifdef PRIORITY_QUEUE_TEST_DEBUG
  std::ostream &os = std::cout;
#else
  null_stream os;
#endif

  print_range(os, "elements: ", first, last);

  print_range(os, "sorted elements: ", keys_copy.begin(), keys_copy.end());
  os << std::endl;

  std::vector<int> min_elements_sort, min_elements_heap;

  // using the heap
  min_k_elements<false>::apply(first, last, k,
                               std::back_inserter(min_elements_heap));

  os << "min " << k << " elements (heap): ";
  print_range(os, min_elements_heap.begin(), min_elements_heap.end());

  std::sort(min_elements_heap.begin(), min_elements_heap.end());
  os << "min " << k << " elements (hp/s): ";
  print_range(os, min_elements_heap.begin(), min_elements_heap.end());
  os << std::endl;

  // using sorting
  min_k_elements<true>::apply(first, last, k,
                              std::back_inserter(min_elements_sort));

  os << "min " << k << " elements (sort): ";
  print_range(os, min_elements_sort.begin(), min_elements_sort.end());
  os << std::endl;

  ASSERT_TRUE(std::equal(min_elements_sort.begin(), min_elements_sort.end(),
                         min_elements_heap.begin()));
}

//--------------------------------------------------------

template <typename Queue>
inline void print_update_msg(std::ostream &os, std::string header,
                             Queue const &q, typename Queue::size_type pos,
                             typename Queue::value_type const &old_value,
                             typename Queue::value_type const &new_value) {
  os << header << " priority of element " << old_value << " at position " << pos
     << " to new value " << new_value << "; new_queue: " << q << std::endl;
}

template <typename RandomAccessIterator>
inline void test_heap(RandomAccessIterator first, RandomAccessIterator last) {
  typedef typename std::iterator_traits<RandomAccessIterator>::value_type
      value_type;

  typedef Priority_queue<value_type> queue;
  typedef typename queue::size_type size_type;
  typedef typename queue::iterator iterator;
  typedef typename queue::const_iterator const_iterator;

#ifdef PRIORITY_QUEUE_TEST_DEBUG
  std::ostream &os = std::cout;
#else
  null_stream os;
#endif

  queue pq;

  for (RandomAccessIterator it = first; it != last; ++it) {
    EXPECT_FALSE(pq.push(*it));
    ASSERT_TRUE(pq.is_valid());
    os << "queue: " << pq << std::endl;
  }

  // test constructor with iterators
  {
    queue pq2(first, last);
    ASSERT_TRUE(pq2.is_valid());
    os << "queue (constructor with iterators): " << pq2 << std::endl;
  }

  // test top
  os << "top element: " << pq.top() << std::endl;
  ASSERT_TRUE(pq.top() == pq[0]);

  // test push
  value_type new_value = *std::min_element(pq.begin(), pq.end()) - 1;
  EXPECT_FALSE(pq.push(new_value));
  ASSERT_TRUE(pq.is_valid());
  os << "pushed " << new_value << "; new queue: " << pq << std::endl;

  // test pop
  pq.pop();
  ASSERT_TRUE(pq.is_valid());
  os << "popped top element; new queue: " << pq << std::endl;

  // test decrease
  // decrease priority of element at position 3
  {
    size_type pos = 3;
    value_type old_priority = pq[pos];
    value_type new_priority = pq[pos];
    pq.decrease(pos, new_priority);
    ASSERT_TRUE(pq.is_valid());
    print_update_msg(os, "decreasing (2)", pq, pos, old_priority, new_priority);

    old_priority = pq[pos];
    new_priority = pq[pos];
    *(pq.begin() + pos) = new_priority;
    pq.decrease(pos);
    ASSERT_TRUE(pq.is_valid());
    print_update_msg(os, "decreasing (1)", pq, pos, old_priority, new_priority);

    old_priority = pq[pos];
    new_priority = pq[pos] - 10;
    pq.decrease(pos, new_priority);
    ASSERT_TRUE(pq.is_valid());
    print_update_msg(os, "decreasing (2)", pq, pos, old_priority, new_priority);

    old_priority = pq[pos];
    new_priority = pq[pos] - 20;
    pq[pos] = new_priority;
    pq.decrease(pos);
    ASSERT_TRUE(pq.is_valid());
    print_update_msg(os, "decreasing (1)", pq, pos, old_priority, new_priority);
  }

  // test increase
  // increase priority of element at position 4
  {
    size_type pos = 4;
    value_type old_priority = pq[pos];
    value_type new_priority = pq[pos];
    pq.increase(pos, new_priority);
    ASSERT_TRUE(pq.is_valid());
    print_update_msg(os, "increasing (2)", pq, pos, old_priority, new_priority);

    old_priority = pq[pos];
    new_priority = pq[pos];
    *(pq.begin() + pos) = new_priority;
    pq.increase(pos);
    ASSERT_TRUE(pq.is_valid());
    print_update_msg(os, "increasing (1)", pq, pos, old_priority, new_priority);

    old_priority = pq[pos];
    new_priority = pq[pos] + 30;
    pq.increase(pos, new_priority);
    ASSERT_TRUE(pq.is_valid());
    print_update_msg(os, "increasing (2)", pq, pos, old_priority, new_priority);

    old_priority = pq[pos];
    new_priority = pq[pos] + 50;
    pq[pos] = new_priority;
    pq.increase(pos);
    ASSERT_TRUE(pq.is_valid());
    print_update_msg(os, "increasing (1)", pq, pos, old_priority, new_priority);
  }

  // test update
  // update priority of element at position 2
  {
    size_type pos = 2;
    value_type old_priority = pq[pos];
    value_type new_priority = pq[pos];
    pq.update(pos, new_priority);
    ASSERT_TRUE(pq.is_valid());
    print_update_msg(os, "updating (2)", pq, pos, old_priority, new_priority);

    old_priority = pq[pos];
    new_priority = pq[pos];
    *(pq.begin() + pos) = new_priority;
    pq.update(pos);
    ASSERT_TRUE(pq.is_valid());
    print_update_msg(os, "updating (1)", pq, pos, old_priority, new_priority);

    old_priority = pq[pos];
    new_priority = pq[pos] - 20;
    *(pq.begin() + pos) = new_priority;
    pq.update(pos);
    ASSERT_TRUE(pq.is_valid());
    print_update_msg(os, "updating (2)", pq, pos, old_priority, new_priority);

    old_priority = pq[pos];
    new_priority = pq[pos] + 100;
    pq[pos] = new_priority;
    pq.update(pos);
    ASSERT_TRUE(pq.is_valid());
    print_update_msg(os, "updating (1)", pq, pos, old_priority, new_priority);
  }

  // test size
  ASSERT_TRUE(pq.size() == static_cast<size_t>(std::distance(first, last)));
  ASSERT_TRUE(pq.is_valid());
  os << "size: " << pq.size() << std::endl;

  // test empty
  ASSERT_TRUE(!pq.empty());
  ASSERT_TRUE(pq.is_valid());
  os << "empty? " << std::boolalpha << pq.empty() << std::noboolalpha
     << std::endl;

  // print all elements in queue using operator[]
  os << "queue (using operator[]):";
  for (size_type i = 0; i < pq.size(); ++i) {
    os << " " << pq[i];
  }
  os << std::endl;

  // print all elements in queue using const/non-const iterators
  os << "queue (using const iterators):";
  for (const_iterator it = pq.begin(); it != pq.end(); ++it) {
    os << " " << *it;
  }
  os << std::endl;

  os << "queue (using non-const iterators):";
  for (iterator it = pq.begin(); it != pq.end(); ++it) {
    os << " " << *it;
  }
  os << std::endl;

  // testing swap
  queue other;

  ASSERT_TRUE(pq.is_valid() && !pq.empty());
  ASSERT_TRUE(other.is_valid() && other.empty());
  os << "before swap: " << pq << "; " << other << std::endl;
  pq.swap(other);
  ASSERT_TRUE(pq.is_valid() && pq.empty());
  ASSERT_TRUE(other.is_valid() && !other.empty());
  os << "after swap: " << pq << "; " << other << std::endl;

  // clear the heap
  pq.clear();
  ASSERT_TRUE(pq.is_valid());
  ASSERT_TRUE(pq.empty());
  os << "clearing the queue" << std::endl;

  // reserve 10 heap elements and push 10 elements in the heap
  os << "testing reserve" << std::endl;
  ASSERT_TRUE(pq.empty());
  ASSERT_FALSE(pq.reserve(2 * pq.capacity()));
  ASSERT_TRUE(pq.empty());
  for (size_type i = 0; i < static_cast<size_t>(std::distance(first, last));
       ++i) {
    ASSERT_TRUE(pq.size() == i);
    EXPECT_FALSE(pq.push(*(last - 1 - i)));
    ASSERT_TRUE(pq.is_valid());
    os << "queue: " << pq << std::endl;
  }

  // now use the non-const top() method to update the root element
  os << "testing non-const top()" << std::endl;
  {
    value_type old_priority = pq.top();
    value_type new_priority = pq.top() - 40;
    pq.top() = pq.top() - 40;
    pq.update(0);
    ASSERT_TRUE(pq.is_valid());
    print_update_msg(os, "updating (using top)", pq, 0, old_priority,
                     new_priority);
  }
}

//--------------------------------------------------------

template <typename RandomAccessIterator>
inline void test_heap_of_handles(RandomAccessIterator first,
                                 RandomAccessIterator last) {
  typedef typename std::iterator_traits<RandomAccessIterator>::value_type
      value_type;

  typedef handle<value_type> handle_type;

  typedef handle_less<handle_type, value_type, std::greater<value_type>>
      handle_greater_type;

  typedef Priority_queue<handle_type, std::vector<handle_type>,
                         handle_less<handle_type, value_type>>
      queue;

  typedef typename queue::const_iterator const_iterator;

#ifdef PRIORITY_QUEUE_TEST_DEBUG
  std::ostream &os = std::cout;
#else
  null_stream os;
#endif

  size_t const N = static_cast<size_t>(std::distance(first, last));

  std::vector<handle_type> handles;
  for (size_t i = 0; i < N; ++i) {
    handles.push_back(handle_type(*(first + i)));
  }
  for (size_t i = 0; i < N; ++i) {
    os << handles[i] << std::endl;
  }

  queue pq;
  for (size_t i = 0; i < N; ++i) {
    EXPECT_FALSE(pq.push(handles[i]));
    ASSERT_TRUE(pq.is_valid());
    os << "queue: " << pq << std::endl;
  }

  {
    queue pq2(handles.begin(), handles.end());
    ASSERT_TRUE(pq2.is_valid());
    os << "queue: " << pq2 << std::endl;
  }

  const_iterator it_max =
      std::max_element(pq.begin(), pq.end(), handle_greater_type());
  *pq[0].ptr = *it_max->ptr + 1000;
  os << "queue: " << pq << std::endl;
  pq.update_top();
  ASSERT_TRUE(pq.is_valid());
  os << "queue: " << pq << std::endl;

  it_max = std::max_element(pq.begin(), pq.end(), handle_greater_type());
  *pq[0].ptr = *it_max->ptr + 500;
  os << "queue: " << pq << std::endl;
  pq.update_top();
  ASSERT_TRUE(pq.is_valid());
  os << "queue: " << pq << std::endl;
}

//--------------------------------------------------------

class PriorityQueueTest : public ::testing::Test {
 protected:
  virtual void SetUp() {
    int xkeys[10] = {10, 4, 7, 8, 21, -5, 6, 10, 7, 9};
    memcpy(keys, xkeys, sizeof(xkeys));
    pq = Priority_queue<int>(xkeys, xkeys + 10);
    keys2.assign(5, 50);
  }

  size_t parent(size_t i) { return Priority_queue<int>::parent(i); }
  size_t left(size_t i) { return Priority_queue<int>::left(i); }
  size_t right(size_t i) { return Priority_queue<int>::right(i); }

  int keys[10];
  Priority_queue<int> pq;
  std::vector<unsigned> keys2;
};

TEST_F(PriorityQueueTest, ParentLeftRight) {
  EXPECT_EQ(0U, parent(1));
  EXPECT_EQ(0U, parent(2));
  EXPECT_EQ(1U, left(0));
  EXPECT_EQ(2U, right(0));
  for (size_t ix = 0; ix < 42; ++ix) {
    EXPECT_EQ(ix, parent(left(ix)));
    EXPECT_EQ(ix, parent(right(ix)));
    EXPECT_EQ(1 + left(ix), right(ix));
  }
}

struct My_less {
  bool operator()(int a, int b) const { return a < b; }
};

struct My_greater {
  bool operator()(int a, int b) const { return a > b; }
};

TEST_F(PriorityQueueTest, MaxVsMinHeap) {
  Priority_queue<int, std::vector<int>, My_less> pql;
  Priority_queue<int, std::vector<int>, My_greater> pqg;
  for (int ix = 0; ix < 10; ++ix) {
    EXPECT_FALSE(pql.push(ix));
    EXPECT_FALSE(pqg.push(ix));
    EXPECT_EQ(ix, pql.top());
    EXPECT_EQ(0, pqg.top());
    EXPECT_TRUE(pql.is_valid());
    EXPECT_TRUE(pqg.is_valid());
  }
  std::stringstream ss1, ss2;
  ss1 << pql;
  EXPECT_STREQ("9 8 5 6 7 1 4 0 3 2 ", ss1.str().c_str());
  ss2 << pqg;
  EXPECT_STREQ("0 1 2 3 4 5 6 7 8 9 ", ss2.str().c_str());
}

TEST_F(PriorityQueueTest, DifferentCtors) {
  Priority_queue<int, std::vector<int>, My_less> pql;
  std::vector<int> intvec;
  for (int ix = 0; ix < 10; ++ix) {
    Priority_queue<int> pq_ix(intvec.begin(), intvec.end());
    EXPECT_TRUE(pq_ix.is_valid());
    EXPECT_FALSE(pql.push(ix));
    EXPECT_EQ(ix, pql.top());
    intvec.push_back(ix);
  }
  Priority_queue<int, std::vector<int>, My_less> pql_range(intvec.begin(),
                                                           intvec.end());

  EXPECT_EQ(10U, pql.size());
  EXPECT_FALSE(pql.empty());
  EXPECT_TRUE(pql.is_valid());
  EXPECT_EQ(10U, pql_range.size());
  EXPECT_FALSE(pql_range.empty());
  EXPECT_TRUE(pql_range.is_valid());

  std::stringstream ss1, ss2;
  ss1 << pql;
  ss2 << pql_range;
  // Different heaps, both are valid:
  EXPECT_STREQ("9 8 5 6 7 1 4 0 3 2 ", ss1.str().c_str());
  EXPECT_STREQ("9 8 6 7 4 5 2 0 3 1 ", ss2.str().c_str());
}

TEST_F(PriorityQueueTest, Swap) {
  std::random_shuffle(keys, keys + 10);
  Priority_queue<int> pq(keys, keys + 10);
  std::stringstream ss1, ss2;
  ss1 << pq;
  Priority_queue<int> pq_swap;
  pq_swap.swap(pq);
  ss2 << pq_swap;
  EXPECT_STREQ(ss1.str().c_str(), ss2.str().c_str());
  EXPECT_EQ(0U, pq.size());
}

TEST_F(PriorityQueueTest, DecreaseNoop) {
  std::stringstream ss1, ss2;
  ss1 << pq;
  for (size_t ix = 0; ix < 10; ++ix) {
    pq.decrease(ix);
    int val = pq[ix];
    pq.decrease(ix, val);
    *(pq.begin() + ix) = val;
    pq.decrease(ix);
    EXPECT_TRUE(pq.is_valid());
  }
  ss2 << pq;
  EXPECT_STREQ(ss1.str().c_str(), ss2.str().c_str());
}

TEST_F(PriorityQueueTest, IncreaseNoop) {
  std::stringstream ss1, ss2;
  ss1 << pq;
  for (size_t ix = 0; ix < 10; ++ix) {
    pq.increase(ix);
    int val = pq[ix];
    pq.increase(ix, val);
    *(pq.begin() + ix) = val;
    pq.increase(ix);
    EXPECT_TRUE(pq.is_valid());
  }
  ss2 << pq;
  EXPECT_STREQ(ss1.str().c_str(), ss2.str().c_str());
}

TEST_F(PriorityQueueTest, UpdateNoop) {
  std::stringstream ss1, ss2;
  ss1 << pq;
  for (size_t ix = 0; ix < 10; ++ix) {
    pq.update(ix);
    int val = pq[ix];
    pq.update(ix, val);
    *(pq.begin() + ix) = val;
    pq.update(ix);
    EXPECT_TRUE(pq.is_valid());
  }
  ss2 << pq;
  EXPECT_STREQ(ss1.str().c_str(), ss2.str().c_str());
}

TEST_F(PriorityQueueTest, Decrease3) {
  Priority_queue<int> pqcopy = pq;
  const int old_priority = pq[3];
  const int new_priority = old_priority - rand() / 2;

  pq.decrease(3, new_priority);
  pqcopy[3] = new_priority;
  pqcopy.decrease(3);

  std::stringstream ss1, ss2;
  ss1 << pq;
  ss2 << pqcopy;
  EXPECT_TRUE(pq.is_valid());
  EXPECT_TRUE(pqcopy.is_valid());
  EXPECT_STREQ(ss1.str().c_str(), ss2.str().c_str());
}

TEST_F(PriorityQueueTest, Increase4) {
  Priority_queue<int> pqcopy = pq;
  const int old_priority = pq[4];
  const int new_priority = old_priority + rand() / 2;

  pq.increase(4, new_priority);
  pqcopy[4] = new_priority;
  pqcopy.increase(4);

  std::stringstream ss1, ss2;
  ss1 << pq;
  ss2 << pqcopy;
  EXPECT_TRUE(pq.is_valid());
  EXPECT_TRUE(pqcopy.is_valid());
  EXPECT_STREQ(ss1.str().c_str(), ss2.str().c_str());
}

TEST_F(PriorityQueueTest, Update2) {
  Priority_queue<int> pqcopy = pq;

  for (int i = -10; i <= 10; ++i) {
    const int old_priority = pq[2];
    const int new_priority = old_priority + i;

    pq.update(2, new_priority);
    pqcopy[2] = new_priority;
    pqcopy.update(2);

    std::stringstream ss1, ss2;
    ss1 << pq;
    ss2 << pqcopy;
    EXPECT_TRUE(pq.is_valid()) << "i:" << i << " pq:" << pq;
    EXPECT_TRUE(pqcopy.is_valid());
    EXPECT_STREQ(ss1.str().c_str(), ss2.str().c_str());
  }
}

TEST_F(PriorityQueueTest, UpdateTop) {
  Priority_queue<int> pqcopy = pq;
  const int old_priority = pq.top();
  const int new_priority = old_priority + 10;

  pq.top() = new_priority;
  pq.update_top();
  pqcopy.update(0, new_priority);
  std::stringstream ss1, ss2;
  ss1 << pq;
  ss2 << pqcopy;
  EXPECT_TRUE(pq.is_valid());
  EXPECT_TRUE(pqcopy.is_valid());
  EXPECT_STREQ(ss1.str().c_str(), ss2.str().c_str());
}

TEST_F(PriorityQueueTest, PopAndRemove) {
  Priority_queue<int> pqcopy = pq;

  EXPECT_TRUE(pqcopy.size() == 10U);
  pqcopy.pop();
  EXPECT_TRUE(pqcopy.is_valid());
  EXPECT_TRUE(pqcopy.size() == 9U);
  pqcopy.remove(3);
  EXPECT_TRUE(pqcopy.is_valid());
  EXPECT_TRUE(pqcopy.size() == 8U);
  pqcopy.remove(pqcopy.size() - 1);
  EXPECT_TRUE(pqcopy.is_valid());
  EXPECT_TRUE(pqcopy.size() == 7U);

  Priority_queue<int> singleton;
  EXPECT_FALSE(singleton.push(10));
  singleton.pop();
  EXPECT_TRUE(singleton.empty());
  EXPECT_TRUE(singleton.is_valid());
}

TEST_F(PriorityQueueTest, Iterators) {
  Priority_queue<int>::iterator it;
  Priority_queue<int>::const_iterator cit;
  std::stringstream ss1, ss2;
  for (it = pq.begin(); it != pq.end(); ++it) ss1 << *it << " ";
  for (cit = pq.begin(); cit != pq.end(); ++cit) ss2 << *cit << " ";
  EXPECT_STREQ(ss1.str().c_str(), ss2.str().c_str());
}

TEST_F(PriorityQueueTest, Clear) {
  EXPECT_EQ(10U, pq.size());
  EXPECT_TRUE(pq.is_valid());
  pq.clear();
  EXPECT_EQ(0U, pq.size());
  EXPECT_TRUE(pq.is_valid());
}

TEST_F(PriorityQueueTest, Reserve) {
  EXPECT_EQ(10U, pq.capacity());
  EXPECT_EQ(10U, pq.size());
  EXPECT_FALSE(pq.reserve(10));
  EXPECT_EQ(10U, pq.capacity());
  EXPECT_EQ(10U, pq.size());
  EXPECT_FALSE(pq.reserve(5));
  EXPECT_EQ(10U, pq.capacity());
  EXPECT_EQ(10U, pq.size());
  EXPECT_FALSE(pq.reserve(20));
  EXPECT_EQ(20U, pq.capacity());
  EXPECT_EQ(10U, pq.size());
}

TEST_F(PriorityQueueTest, Sort) {
  Priority_queue<int> pqcopy = pq;
  std::vector<int> keyscopy(keys, keys + 10);

  pqcopy.sort();
  std::sort(keyscopy.begin(), keyscopy.end());

  std::stringstream ss1, ss2;
  ss1 << pqcopy;
  for (size_t i = 0; i < keyscopy.size(); ++i) {
    ss2 << keyscopy[i] << " ";
  }
  EXPECT_STREQ(ss1.str().c_str(), ss2.str().c_str());
}

TEST_F(PriorityQueueTest, TestHeapKeys) {
  SCOPED_TRACE("");
  test_heap(keys, keys + 10);
}

TEST_F(PriorityQueueTest, TestHeapKeys2) {
  SCOPED_TRACE("");
  test_heap(keys2.begin(), keys2.end());
}

TEST_F(PriorityQueueTest, TestHeapOfHandles) {
  SCOPED_TRACE("");
  test_heap_of_handles(keys, keys + 10);
}

TEST_F(PriorityQueueTest, TestHeapOfHandles2) {
  SCOPED_TRACE("");
  test_heap_of_handles(keys2.begin(), keys2.end());
}

TEST_F(PriorityQueueTest, TestMinKElements) {
  SCOPED_TRACE("");
  test_min_k_elements(keys, keys + 10, 7);
}

TEST_F(PriorityQueueTest, TestMinKElements2) {
  SCOPED_TRACE("");
  test_min_k_elements(keys2.begin(), keys2.end(), 4);
}

TEST_F(PriorityQueueTest, RandomIntegerGenerator) {
  random_integer_generator<int> g;
  std::vector<int> many_keys;

  for (int i = 0; i < 200; ++i) {
    int value = g(0, 300);
    many_keys.push_back(value);
  }

  SCOPED_TRACE("");
  test_min_k_elements(many_keys.begin(), many_keys.end(), 20);
}

}  // namespace priority_queue_unittest