compiler/utils/intrusive_forward_list_test.cc

/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * 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 <algorithm>
#include <forward_list>
#include <vector>

#include "gtest/gtest.h"
#include "intrusive_forward_list.h"

namespace art {

struct IFLTestValue {
  // Deliberately not explicit.
  IFLTestValue(int v) : hook(), value(v) { }  // NOLINT(runtime/explicit)

  IntrusiveForwardListHook hook;
  int value;
};

bool operator==(const IFLTestValue& lhs, const IFLTestValue& rhs) {
  return lhs.value == rhs.value;
}

bool operator<(const IFLTestValue& lhs, const IFLTestValue& rhs) {
  return lhs.value < rhs.value;
}

#define ASSERT_LISTS_EQUAL(expected, value)                                   \
  do {                                                                        \
    ASSERT_EQ(expected.empty(), value.empty());                               \
    ASSERT_EQ(std::distance(expected.begin(), expected.end()),                \
              std::distance(value.begin(), value.end()));                     \
    ASSERT_TRUE(std::equal(expected.begin(), expected.end(), value.begin())); \
  } while (false)

TEST(IntrusiveForwardList, IteratorToConstIterator) {
  IntrusiveForwardList<IFLTestValue> ifl;
  IntrusiveForwardList<IFLTestValue>::iterator begin = ifl.begin();
  IntrusiveForwardList<IFLTestValue>::const_iterator cbegin = ifl.cbegin();
  IntrusiveForwardList<IFLTestValue>::const_iterator converted_begin = begin;
  ASSERT_TRUE(converted_begin == cbegin);
}

TEST(IntrusiveForwardList, IteratorOperators) {
  IntrusiveForwardList<IFLTestValue> ifl;
  ASSERT_TRUE(ifl.begin() == ifl.cbegin());
  ASSERT_FALSE(ifl.begin() != ifl.cbegin());
  ASSERT_TRUE(ifl.end() == ifl.cend());
  ASSERT_FALSE(ifl.end() != ifl.cend());

  ASSERT_TRUE(ifl.begin() == ifl.end());  // Empty.
  ASSERT_FALSE(ifl.begin() != ifl.end());  // Empty.

  IFLTestValue value(1);
  ifl.insert_after(ifl.cbefore_begin(), value);

  ASSERT_FALSE(ifl.begin() == ifl.end());  // Not empty.
  ASSERT_TRUE(ifl.begin() != ifl.end());  // Not empty.
}

TEST(IntrusiveForwardList, ConstructRange) {
  std::forward_list<int> ref({ 1, 2, 7 });
  std::vector<IFLTestValue> storage(ref.begin(), ref.end());
  IntrusiveForwardList<IFLTestValue> ifl(storage.begin(), storage.end());
  ASSERT_LISTS_EQUAL(ref, ifl);
}

TEST(IntrusiveForwardList, Assign) {
  std::forward_list<int> ref1({ 2, 8, 5 });
  std::vector<IFLTestValue> storage1(ref1.begin(), ref1.end());
  IntrusiveForwardList<IFLTestValue> ifl;
  ifl.assign(storage1.begin(), storage1.end());
  ASSERT_LISTS_EQUAL(ref1, ifl);
  std::forward_list<int> ref2({ 7, 1, 3 });
  std::vector<IFLTestValue> storage2(ref2.begin(), ref2.end());
  ifl.assign(storage2.begin(), storage2.end());
  ASSERT_LISTS_EQUAL(ref2, ifl);
}

TEST(IntrusiveForwardList, PushPop) {
  IFLTestValue value3(3);
  IFLTestValue value7(7);
  std::forward_list<int> ref;
  IntrusiveForwardList<IFLTestValue> ifl;
  ASSERT_LISTS_EQUAL(ref, ifl);
  ref.push_front(3);
  ifl.push_front(value3);
  ASSERT_LISTS_EQUAL(ref, ifl);
  ASSERT_EQ(3, ifl.front());
  ref.push_front(7);
  ifl.push_front(value7);
  ASSERT_LISTS_EQUAL(ref, ifl);
  ASSERT_EQ(7, ifl.front());
  ref.pop_front();
  ifl.pop_front();
  ASSERT_LISTS_EQUAL(ref, ifl);
  ASSERT_EQ(3, ifl.front());
  ref.pop_front();
  ifl.pop_front();
  ASSERT_LISTS_EQUAL(ref, ifl);
}

TEST(IntrusiveForwardList, InsertAfter1) {
  IFLTestValue value4(4);
  IFLTestValue value8(8);
  IFLTestValue value5(5);
  IFLTestValue value3(3);
  std::forward_list<int> ref;
  IntrusiveForwardList<IFLTestValue> ifl;

  auto ref_it = ref.insert_after(ref.before_begin(), 4);
  auto ifl_it = ifl.insert_after(ifl.before_begin(), value4);
  ASSERT_LISTS_EQUAL(ref, ifl);
  ASSERT_EQ(*ref_it, *ifl_it);
  CHECK(ref_it == ref.begin());
  ASSERT_TRUE(ifl_it == ifl.begin());

  ref_it = ref.insert_after(ref.begin(), 8);
  ifl_it = ifl.insert_after(ifl.begin(), value8);
  ASSERT_LISTS_EQUAL(ref, ifl);
  ASSERT_EQ(*ref_it, *ifl_it);
  CHECK(ref_it != ref.end());
  ASSERT_TRUE(ifl_it != ifl.end());
  CHECK(++ref_it == ref.end());
  ASSERT_TRUE(++ifl_it == ifl.end());

  ref_it = ref.insert_after(ref.begin(), 5);
  ifl_it = ifl.insert_after(ifl.begin(), value5);
  ASSERT_LISTS_EQUAL(ref, ifl);
  ASSERT_EQ(*ref_it, *ifl_it);

  ref_it = ref.insert_after(ref_it, 3);
  ifl_it = ifl.insert_after(ifl_it, value3);
  ASSERT_LISTS_EQUAL(ref, ifl);
  ASSERT_EQ(*ref_it, *ifl_it);
}

TEST(IntrusiveForwardList, InsertAfter2) {
  std::forward_list<int> ref;
  IntrusiveForwardList<IFLTestValue> ifl;

  auto ref_it = ref.insert_after(ref.before_begin(), { 2, 8, 5 });
  std::vector<IFLTestValue> storage1({ { 2 }, { 8 }, { 5 } });
  auto ifl_it = ifl.insert_after(ifl.before_begin(), storage1.begin(), storage1.end());
  ASSERT_LISTS_EQUAL(ref, ifl);
  ASSERT_EQ(*ref_it, *ifl_it);

  std::vector<IFLTestValue> storage2({ { 7 }, { 2 } });
  ref_it = ref.insert_after(ref.begin(), { 7, 2 });
  ifl_it = ifl.insert_after(ifl.begin(), storage2.begin(), storage2.end());
  ASSERT_LISTS_EQUAL(ref, ifl);
  ASSERT_EQ(*ref_it, *ifl_it);

  std::vector<IFLTestValue> storage3({ { 1 }, { 3 }, { 4 }, { 9 } });
  ref_it = ref.begin();
  ifl_it = ifl.begin();
  std::advance(ref_it, std::distance(ref.begin(), ref.end()) - 1);
  std::advance(ifl_it, std::distance(ifl.begin(), ifl.end()) - 1);
  ref_it = ref.insert_after(ref_it, { 1, 3, 4, 9 });
  ifl_it = ifl.insert_after(ifl_it, storage3.begin(), storage3.end());
  ASSERT_LISTS_EQUAL(ref, ifl);
}

TEST(IntrusiveForwardList, EraseAfter1) {
  std::forward_list<int> ref({ 1, 2, 7, 4, 5 });
  std::vector<IFLTestValue> storage(ref.begin(), ref.end());
  IntrusiveForwardList<IFLTestValue> ifl(storage.begin(), storage.end());
  ASSERT_LISTS_EQUAL(ref, ifl);
  CHECK_EQ(std::distance(ref.begin(), ref.end()), 5);

  auto ref_it = ref.begin();
  auto ifl_it = ifl.begin();
  std::advance(ref_it, 2);
  std::advance(ifl_it, 2);
  ref_it = ref.erase_after(ref_it);
  ifl_it = ifl.erase_after(ifl_it);
  ASSERT_LISTS_EQUAL(ref, ifl);
  CHECK_EQ(std::distance(ref.begin(), ref.end()), 4);
  CHECK(ref_it != ref.end());
  ASSERT_TRUE(ifl_it != ifl.end());
  CHECK(++ref_it == ref.end());
  ASSERT_TRUE(++ifl_it == ifl.end());

  ref_it = ref.begin();
  ifl_it = ifl.begin();
  std::advance(ref_it, 2);
  std::advance(ifl_it, 2);
  ref_it = ref.erase_after(ref_it);
  ifl_it = ifl.erase_after(ifl_it);
  ASSERT_LISTS_EQUAL(ref, ifl);
  CHECK_EQ(std::distance(ref.begin(), ref.end()), 3);
  CHECK(ref_it == ref.end());
  ASSERT_TRUE(ifl_it == ifl.end());

  ref_it = ref.erase_after(ref.begin());
  ifl_it = ifl.erase_after(ifl.begin());
  ASSERT_LISTS_EQUAL(ref, ifl);
  CHECK_EQ(std::distance(ref.begin(), ref.end()), 2);
  CHECK(ref_it != ref.end());
  ASSERT_TRUE(ifl_it != ifl.end());
  CHECK(++ref_it == ref.end());
  ASSERT_TRUE(++ifl_it == ifl.end());

  ref_it = ref.erase_after(ref.before_begin());
  ifl_it = ifl.erase_after(ifl.before_begin());
  ASSERT_LISTS_EQUAL(ref, ifl);
  CHECK_EQ(std::distance(ref.begin(), ref.end()), 1);
  CHECK(ref_it == ref.begin());
  ASSERT_TRUE(ifl_it == ifl.begin());

  ref_it = ref.erase_after(ref.before_begin());
  ifl_it = ifl.erase_after(ifl.before_begin());
  ASSERT_LISTS_EQUAL(ref, ifl);
  CHECK_EQ(std::distance(ref.begin(), ref.end()), 0);
  CHECK(ref_it == ref.begin());
  ASSERT_TRUE(ifl_it == ifl.begin());
}

TEST(IntrusiveForwardList, EraseAfter2) {
  std::forward_list<int> ref({ 1, 2, 7, 4, 5, 3, 2, 8, 9 });
  std::vector<IFLTestValue> storage(ref.begin(), ref.end());
  IntrusiveForwardList<IFLTestValue> ifl(storage.begin(), storage.end());
  ASSERT_LISTS_EQUAL(ref, ifl);
  CHECK_EQ(std::distance(ref.begin(), ref.end()), 9);

  auto ref_it = ref.begin();
  auto ifl_it = ifl.begin();
  std::advance(ref_it, 3);
  std::advance(ifl_it, 3);
  ref_it = ref.erase_after(ref.begin(), ref_it);
  ifl_it = ifl.erase_after(ifl.begin(), ifl_it);
  ASSERT_LISTS_EQUAL(ref, ifl);
  ASSERT_EQ(std::distance(ref.begin(), ref_it), std::distance(ifl.begin(), ifl_it));
  CHECK_EQ(std::distance(ref.begin(), ref.end()), 7);

  ref_it = ref.erase_after(ref_it, ref.end());
  ifl_it = ifl.erase_after(ifl_it, ifl.end());
  ASSERT_LISTS_EQUAL(ref, ifl);
  CHECK(ref_it == ref.end());
  ASSERT_TRUE(ifl_it == ifl.end());
  CHECK_EQ(std::distance(ref.begin(), ref.end()), 2);

  ref_it = ref.erase_after(ref.before_begin(), ref.end());
  ifl_it = ifl.erase_after(ifl.before_begin(), ifl.end());
  ASSERT_LISTS_EQUAL(ref, ifl);
  CHECK(ref_it == ref.end());
  ASSERT_TRUE(ifl_it == ifl.end());
  CHECK_EQ(std::distance(ref.begin(), ref.end()), 0);
}

TEST(IntrusiveForwardList, SwapClear) {
  std::forward_list<int> ref1({ 1, 2, 7 });
  std::vector<IFLTestValue> storage1(ref1.begin(), ref1.end());
  IntrusiveForwardList<IFLTestValue> ifl1(storage1.begin(), storage1.end());
  std::forward_list<int> ref2({ 3, 8, 6 });
  std::vector<IFLTestValue> storage2(ref2.begin(), ref2.end());
  IntrusiveForwardList<IFLTestValue> ifl2(storage2.begin(), storage2.end());
  ASSERT_LISTS_EQUAL(ref1, ifl1);
  ASSERT_LISTS_EQUAL(ref2, ifl2);
  ref1.swap(ref2);
  ifl1.swap(ifl2);
  ASSERT_LISTS_EQUAL(ref1, ifl1);
  ASSERT_LISTS_EQUAL(ref2, ifl2);
  ref1.clear();
  ifl1.clear();
  ASSERT_LISTS_EQUAL(ref1, ifl1);
  ASSERT_LISTS_EQUAL(ref2, ifl2);
  swap(ref1, ref2);
  swap(ifl1, ifl2);
  ASSERT_LISTS_EQUAL(ref1, ifl1);
  ASSERT_LISTS_EQUAL(ref2, ifl2);
  ref1.clear();
  ifl1.clear();
  ASSERT_LISTS_EQUAL(ref1, ifl1);
  ASSERT_LISTS_EQUAL(ref2, ifl2);
}

TEST(IntrusiveForwardList, SpliceAfter) {
  std::forward_list<int> ref1({ 3, 1, 2, 7, 4, 5, 4, 8, 7 });
  std::forward_list<int> ref2;
  std::vector<IFLTestValue> storage(ref1.begin(), ref1.end());
  IntrusiveForwardList<IFLTestValue> ifl1(storage.begin(), storage.end());
  IntrusiveForwardList<IFLTestValue> ifl2;
  ASSERT_LISTS_EQUAL(ref1, ifl1);
  ASSERT_LISTS_EQUAL(ref2, ifl2);

  // Move everything to ref2/ifl2.
  ref2.splice_after(ref2.before_begin(), ref1);
  ifl2.splice_after(ifl2.before_begin(), ifl1);
  ASSERT_LISTS_EQUAL(ref1, ifl1);
  ASSERT_LISTS_EQUAL(ref2, ifl2);

  // Move first element (3) to ref1/ifl1.
  ref1.splice_after(ref1.before_begin(), ref2, ref2.before_begin());
  ifl1.splice_after(ifl1.before_begin(), ifl2, ifl2.before_begin());
  ASSERT_LISTS_EQUAL(ref1, ifl1);
  ASSERT_LISTS_EQUAL(ref2, ifl2);

  // Move second element (2) to ref1/ifl1 after the first element (3).
  ref1.splice_after(ref1.begin(), ref2, ref2.begin());
  ifl1.splice_after(ifl1.begin(), ifl2, ifl2.begin());
  ASSERT_LISTS_EQUAL(ref1, ifl1);
  ASSERT_LISTS_EQUAL(ref2, ifl2);

  // Move everything from ref2/ifl2 between the 2 elements now in ref1/ifl1.
  ref1.splice_after(ref1.begin(), ref2);
  ifl1.splice_after(ifl1.begin(), ifl2);
  ASSERT_LISTS_EQUAL(ref1, ifl1);
  ASSERT_LISTS_EQUAL(ref2, ifl2);

  std::forward_list<int> check({ 3, 1, 7, 4, 5, 4, 8, 7, 2 });
  ASSERT_LISTS_EQUAL(check, ifl1);
  ASSERT_TRUE(ifl2.empty());

  // Empty splice_after().
  ref2.splice_after(
      ref2.before_begin(), ref1, ref1.before_begin(), ref1.begin());
  ifl2.splice_after(ifl2.before_begin(), ifl1, ifl1.before_begin(), ifl1.begin());
  ASSERT_LISTS_EQUAL(ref1, ifl1);
  ASSERT_LISTS_EQUAL(ref2, ifl2);

  // Move { 1, 7 } to ref2/ifl2.
  auto ref_it = ref1.begin();
  auto ifl_it = ifl1.begin();
  std::advance(ref_it, 3);
  std::advance(ifl_it, 3);
  ref2.splice_after(ref2.before_begin(), ref1, ref1.begin(), ref_it);
  ifl2.splice_after(ifl2.before_begin(), ifl1, ifl1.begin(), ifl_it);
  ASSERT_LISTS_EQUAL(ref1, ifl1);
  ASSERT_LISTS_EQUAL(ref2, ifl2);

  // Move { 8, 7, 2 } to the beginning of ref1/ifl1.
  ref_it = ref1.begin();
  ifl_it = ifl1.begin();
  std::advance(ref_it, 3);
  std::advance(ifl_it, 3);
  ref1.splice_after(ref1.before_begin(), ref1, ref_it, ref1.end());
  ifl1.splice_after(ifl1.before_begin(), ifl1, ifl_it, ifl1.end());
  ASSERT_LISTS_EQUAL(ref1, ifl1);

  check.assign({ 8, 7, 2, 3, 4, 5, 4 });
  ASSERT_LISTS_EQUAL(check, ifl1);
  check.assign({ 1, 7 });
  ASSERT_LISTS_EQUAL(check, ifl2);

  // Move all but the first element to ref2/ifl2.
  ref_it = ref2.begin();
  ifl_it = ifl2.begin();
  std::advance(ref_it, 1);
  std::advance(ifl_it, 1);
  ref2.splice_after(ref_it, ref1, ref1.begin(), ref1.end());
  ifl2.splice_after(ifl_it, ifl1, ifl1.begin(), ifl1.end());
  ASSERT_LISTS_EQUAL(ref1, ifl1);
  ASSERT_LISTS_EQUAL(ref2, ifl2);

  check.assign({8});
  ASSERT_LISTS_EQUAL(check, ifl1);

  // Move the first element of ref1/ifl1 to the beginning of ref1/ifl1 (do nothing).
  ref1.splice_after(ref1.before_begin(), ref1, ref1.before_begin());
  ifl1.splice_after(ifl1.before_begin(), ifl1, ifl1.before_begin());
  ASSERT_LISTS_EQUAL(ref1, ifl1);
  ASSERT_LISTS_EQUAL(check, ifl1);

  // Move the first element of ref2/ifl2 after itself (do nothing).
  ref1.splice_after(ref1.begin(), ref1, ref1.before_begin());
  ifl1.splice_after(ifl1.begin(), ifl1, ifl1.before_begin());
  ASSERT_LISTS_EQUAL(ref1, ifl1);
  ASSERT_LISTS_EQUAL(check, ifl1);

  check.assign({ 1, 7, 7, 2, 3, 4, 5, 4 });
  ASSERT_LISTS_EQUAL(check, ifl2);

  // Move the first element of ref2/ifl2 to the beginning of ref2/ifl2 (do nothing).
  ref2.splice_after(ref2.before_begin(), ref2, ref2.before_begin());
  ifl2.splice_after(ifl2.before_begin(), ifl2, ifl2.before_begin());
  ASSERT_LISTS_EQUAL(ref2, ifl2);
  ASSERT_LISTS_EQUAL(check, ifl2);

  // Move the first element of ref2/ifl2 after itself (do nothing).
  ref2.splice_after(ref2.begin(), ref2, ref2.before_begin());
  ifl2.splice_after(ifl2.begin(), ifl2, ifl2.before_begin());
  ASSERT_LISTS_EQUAL(ref2, ifl2);
  ASSERT_LISTS_EQUAL(check, ifl2);
}

TEST(IntrusiveForwardList, Remove) {
  std::forward_list<int> ref({ 3, 1, 2, 7, 4, 5, 4, 8, 7 });
  std::vector<IFLTestValue> storage(ref.begin(), ref.end());
  IntrusiveForwardList<IFLTestValue> ifl(storage.begin(), storage.end());
  ASSERT_LISTS_EQUAL(ref, ifl);
  ref.remove(1);
  ifl.remove(1);
  ASSERT_LISTS_EQUAL(ref, ifl);
  ref.remove(4);
  ifl.remove(4);
  ASSERT_LISTS_EQUAL(ref, ifl);
  auto odd = [](IFLTestValue value) { return (value.value & 1) != 0; };  // NOLINT(readability/braces)
  ref.remove_if(odd);
  ifl.remove_if(odd);
  ASSERT_LISTS_EQUAL(ref, ifl);
  auto all = [](IFLTestValue value ATTRIBUTE_UNUSED) { return true; };  // NOLINT(readability/braces)
  ref.remove_if(all);
  ifl.remove_if(all);
  ASSERT_LISTS_EQUAL(ref, ifl);
}

TEST(IntrusiveForwardList, Unique) {
  std::forward_list<int> ref({ 3, 1, 1, 2, 3, 3, 7, 7, 4, 4, 5, 7 });
  std::vector<IFLTestValue> storage(ref.begin(), ref.end());
  IntrusiveForwardList<IFLTestValue> ifl(storage.begin(), storage.end());
  ASSERT_LISTS_EQUAL(ref, ifl);
  ref.unique();
  ifl.unique();
  ASSERT_LISTS_EQUAL(ref, ifl);
  std::forward_list<int> check({ 3, 1, 2, 3, 7, 4, 5, 7 });
  ASSERT_LISTS_EQUAL(check, ifl);

  auto bin_pred = [](IFLTestValue lhs, IFLTestValue rhs) {
    return (lhs.value & ~1) == (rhs.value & ~1);
  };
  ref.unique(bin_pred);
  ifl.unique(bin_pred);
  ASSERT_LISTS_EQUAL(ref, ifl);
  check.assign({ 3, 1, 2, 7, 4, 7 });
  ASSERT_LISTS_EQUAL(check, ifl);
}

TEST(IntrusiveForwardList, Merge) {
  std::forward_list<int> ref1({ 1, 4, 8, 8, 12 });
  std::vector<IFLTestValue> storage1(ref1.begin(), ref1.end());
  IntrusiveForwardList<IFLTestValue> ifl1(storage1.begin(), storage1.end());
  std::forward_list<int> ref2({ 3, 5, 6, 7, 9 });
  std::vector<IFLTestValue> storage2(ref2.begin(), ref2.end());
  IntrusiveForwardList<IFLTestValue> ifl2(storage2.begin(), storage2.end());
  ASSERT_LISTS_EQUAL(ref1, ifl1);
  ASSERT_LISTS_EQUAL(ref2, ifl2);
  CHECK(std::is_sorted(ref1.begin(), ref1.end()));
  CHECK(std::is_sorted(ref2.begin(), ref2.end()));
  ref1.merge(ref2);
  ifl1.merge(ifl2);
  ASSERT_LISTS_EQUAL(ref1, ifl1);
  ASSERT_LISTS_EQUAL(ref2, ifl2);
  CHECK(ref2.empty());
  std::forward_list<int> check({ 1, 3, 4, 5, 6, 7, 8, 8, 9, 12 });
  ASSERT_LISTS_EQUAL(check, ifl1);
}

TEST(IntrusiveForwardList, Sort1) {
  std::forward_list<int> ref({ 2, 9, 8, 3, 7, 4, 1, 5, 3, 0 });
  std::vector<IFLTestValue> storage(ref.begin(), ref.end());
  IntrusiveForwardList<IFLTestValue> ifl(storage.begin(), storage.end());
  ASSERT_LISTS_EQUAL(ref, ifl);
  CHECK(!std::is_sorted(ref.begin(), ref.end()));
  ref.sort();
  ifl.sort();
  ASSERT_LISTS_EQUAL(ref, ifl);
  std::forward_list<int> check({ 0, 1, 2, 3, 3, 4, 5, 7, 8, 9 });
  ASSERT_LISTS_EQUAL(check, ifl);
}

TEST(IntrusiveForwardList, Sort2) {
  std::forward_list<int> ref({ 2, 9, 8, 3, 7, 4, 1, 5, 3, 0 });
  std::vector<IFLTestValue> storage(ref.begin(), ref.end());
  IntrusiveForwardList<IFLTestValue> ifl(storage.begin(), storage.end());
  ASSERT_LISTS_EQUAL(ref, ifl);
  auto cmp = [](IFLTestValue lhs, IFLTestValue rhs) {
    return (lhs.value & ~1) < (rhs.value & ~1);
  };
  CHECK(!std::is_sorted(ref.begin(), ref.end(), cmp));
  ref.sort(cmp);
  ifl.sort(cmp);
  ASSERT_LISTS_EQUAL(ref, ifl);
  std::forward_list<int> check({ 1, 0, 2, 3, 3, 4, 5, 7, 9, 8 });
  ASSERT_LISTS_EQUAL(check, ifl);
}

TEST(IntrusiveForwardList, Reverse) {
  std::forward_list<int> ref({ 8, 3, 5, 4, 1, 3 });
  std::vector<IFLTestValue> storage(ref.begin(), ref.end());
  IntrusiveForwardList<IFLTestValue> ifl(storage.begin(), storage.end());
  ASSERT_LISTS_EQUAL(ref, ifl);
  CHECK(!std::is_sorted(ref.begin(), ref.end()));
  ref.reverse();
  ifl.reverse();
  ASSERT_LISTS_EQUAL(ref, ifl);
  std::forward_list<int> check({ 3, 1, 4, 5, 3, 8 });
  ASSERT_LISTS_EQUAL(check, ifl);
}

}  // namespace art