VectorTest.cpp

/*
 * Copyright (C) 2011 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
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 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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#include "wtf/Vector.h"

#include "testing/gtest/include/gtest/gtest.h"
#include "wtf/HashSet.h"
#include "wtf/Optional.h"
#include "wtf/PtrUtil.h"
#include "wtf/text/WTFString.h"
#include <memory>

namespace WTF {

namespace {

TEST(VectorTest, Basic) {
  Vector<int> intVector;
  EXPECT_TRUE(intVector.isEmpty());
  EXPECT_EQ(0ul, intVector.size());
  EXPECT_EQ(0ul, intVector.capacity());
}

TEST(VectorTest, Reverse) {
  Vector<int> intVector;
  intVector.push_back(10);
  intVector.push_back(11);
  intVector.push_back(12);
  intVector.push_back(13);
  intVector.reverse();

  EXPECT_EQ(13, intVector[0]);
  EXPECT_EQ(12, intVector[1]);
  EXPECT_EQ(11, intVector[2]);
  EXPECT_EQ(10, intVector[3]);

  intVector.push_back(9);
  intVector.reverse();

  EXPECT_EQ(9, intVector[0]);
  EXPECT_EQ(10, intVector[1]);
  EXPECT_EQ(11, intVector[2]);
  EXPECT_EQ(12, intVector[3]);
  EXPECT_EQ(13, intVector[4]);
}

TEST(VectorTest, Remove) {
  Vector<int> intVector;
  intVector.push_back(0);
  intVector.push_back(1);
  intVector.push_back(2);
  intVector.push_back(3);

  EXPECT_EQ(4u, intVector.size());
  EXPECT_EQ(0, intVector[0]);
  EXPECT_EQ(1, intVector[1]);
  EXPECT_EQ(2, intVector[2]);
  EXPECT_EQ(3, intVector[3]);

  intVector.remove(2, 0);
  EXPECT_EQ(4u, intVector.size());
  EXPECT_EQ(2, intVector[2]);

  intVector.remove(2, 1);
  EXPECT_EQ(3u, intVector.size());
  EXPECT_EQ(3, intVector[2]);

  intVector.remove(0, 0);
  EXPECT_EQ(3u, intVector.size());
  EXPECT_EQ(0, intVector[0]);

  intVector.remove(0);
  EXPECT_EQ(2u, intVector.size());
  EXPECT_EQ(1, intVector[0]);
}

TEST(VectorTest, Iterator) {
  Vector<int> intVector;
  intVector.push_back(10);
  intVector.push_back(11);
  intVector.push_back(12);
  intVector.push_back(13);

  Vector<int>::iterator it = intVector.begin();
  Vector<int>::iterator end = intVector.end();
  EXPECT_TRUE(end != it);

  EXPECT_EQ(10, *it);
  ++it;
  EXPECT_EQ(11, *it);
  ++it;
  EXPECT_EQ(12, *it);
  ++it;
  EXPECT_EQ(13, *it);
  ++it;

  EXPECT_TRUE(end == it);
}

TEST(VectorTest, ReverseIterator) {
  Vector<int> intVector;
  intVector.push_back(10);
  intVector.push_back(11);
  intVector.push_back(12);
  intVector.push_back(13);

  Vector<int>::reverse_iterator it = intVector.rbegin();
  Vector<int>::reverse_iterator end = intVector.rend();
  EXPECT_TRUE(end != it);

  EXPECT_EQ(13, *it);
  ++it;
  EXPECT_EQ(12, *it);
  ++it;
  EXPECT_EQ(11, *it);
  ++it;
  EXPECT_EQ(10, *it);
  ++it;

  EXPECT_TRUE(end == it);
}

class DestructCounter {
 public:
  explicit DestructCounter(int i, int* destructNumber)
      : m_i(i), m_destructNumber(destructNumber) {}

  ~DestructCounter() { ++(*m_destructNumber); }
  int get() const { return m_i; }

 private:
  int m_i;
  int* m_destructNumber;
};

typedef WTF::Vector<std::unique_ptr<DestructCounter>> OwnPtrVector;

TEST(VectorTest, OwnPtr) {
  int destructNumber = 0;
  OwnPtrVector vector;
  vector.push_back(WTF::wrapUnique(new DestructCounter(0, &destructNumber)));
  vector.push_back(WTF::wrapUnique(new DestructCounter(1, &destructNumber)));
  EXPECT_EQ(2u, vector.size());

  std::unique_ptr<DestructCounter>& counter0 = vector.front();
  ASSERT_EQ(0, counter0->get());
  int counter1 = vector.back()->get();
  ASSERT_EQ(1, counter1);
  ASSERT_EQ(0, destructNumber);

  size_t index = 0;
  for (OwnPtrVector::iterator iter = vector.begin(); iter != vector.end();
       ++iter) {
    std::unique_ptr<DestructCounter>* refCounter = iter;
    EXPECT_EQ(index, static_cast<size_t>(refCounter->get()->get()));
    EXPECT_EQ(index, static_cast<size_t>((*refCounter)->get()));
    index++;
  }
  EXPECT_EQ(0, destructNumber);

  for (index = 0; index < vector.size(); index++) {
    std::unique_ptr<DestructCounter>& refCounter = vector[index];
    EXPECT_EQ(index, static_cast<size_t>(refCounter->get()));
  }
  EXPECT_EQ(0, destructNumber);

  EXPECT_EQ(0, vector[0]->get());
  EXPECT_EQ(1, vector[1]->get());
  vector.remove(0);
  EXPECT_EQ(1, vector[0]->get());
  EXPECT_EQ(1u, vector.size());
  EXPECT_EQ(1, destructNumber);

  std::unique_ptr<DestructCounter> ownCounter1 = std::move(vector[0]);
  vector.remove(0);
  ASSERT_EQ(counter1, ownCounter1->get());
  ASSERT_EQ(0u, vector.size());
  ASSERT_EQ(1, destructNumber);

  ownCounter1.reset();
  EXPECT_EQ(2, destructNumber);

  size_t count = 1025;
  destructNumber = 0;
  for (size_t i = 0; i < count; i++)
    vector.push_front(WTF::wrapUnique(new DestructCounter(i, &destructNumber)));

  // Vector relocation must not destruct std::unique_ptr element.
  EXPECT_EQ(0, destructNumber);
  EXPECT_EQ(count, vector.size());

  OwnPtrVector copyVector;
  vector.swap(copyVector);
  EXPECT_EQ(0, destructNumber);
  EXPECT_EQ(count, copyVector.size());
  EXPECT_EQ(0u, vector.size());

  copyVector.clear();
  EXPECT_EQ(count, static_cast<size_t>(destructNumber));
}

class MoveOnly {
 public:
  explicit MoveOnly(int i = 0) : m_i(i) {}

  MoveOnly(MoveOnly&& other) : m_i(other.m_i) { other.m_i = 0; }

  MoveOnly& operator=(MoveOnly&& other) {
    if (this != &other) {
      m_i = other.m_i;
      other.m_i = 0;
    }
    return *this;
  }

  int value() const { return m_i; }

 private:
  WTF_MAKE_NONCOPYABLE(MoveOnly);
  int m_i;
};

TEST(VectorTest, MoveOnlyType) {
  WTF::Vector<MoveOnly> vector;
  vector.push_back(MoveOnly(1));
  vector.push_back(MoveOnly(2));
  EXPECT_EQ(2u, vector.size());

  ASSERT_EQ(1, vector.front().value());
  ASSERT_EQ(2, vector.back().value());

  vector.remove(0);
  EXPECT_EQ(2, vector[0].value());
  EXPECT_EQ(1u, vector.size());

  MoveOnly moveOnly(std::move(vector[0]));
  vector.remove(0);
  ASSERT_EQ(2, moveOnly.value());
  ASSERT_EQ(0u, vector.size());

  size_t count = vector.capacity() + 1;
  for (size_t i = 0; i < count; i++)
    vector.push_back(
        MoveOnly(i + 1));  // +1 to distinguish from default-constructed.

  // Reallocation did not affect the vector's content.
  EXPECT_EQ(count, vector.size());
  for (size_t i = 0; i < vector.size(); i++)
    EXPECT_EQ(static_cast<int>(i + 1), vector[i].value());

  WTF::Vector<MoveOnly> otherVector;
  vector.swap(otherVector);
  EXPECT_EQ(count, otherVector.size());
  EXPECT_EQ(0u, vector.size());

  vector = std::move(otherVector);
  EXPECT_EQ(count, vector.size());
}

// WrappedInt class will fail if it was memmoved or memcpyed.
static HashSet<void*> constructedWrappedInts;
class WrappedInt {
 public:
  WrappedInt(int i = 0) : m_originalThisPtr(this), m_i(i) {
    constructedWrappedInts.insert(this);
  }

  WrappedInt(const WrappedInt& other)
      : m_originalThisPtr(this), m_i(other.m_i) {
    constructedWrappedInts.insert(this);
  }

  WrappedInt& operator=(const WrappedInt& other) {
    m_i = other.m_i;
    return *this;
  }

  ~WrappedInt() {
    EXPECT_EQ(m_originalThisPtr, this);
    EXPECT_TRUE(constructedWrappedInts.contains(this));
    constructedWrappedInts.erase(this);
  }

  int get() const { return m_i; }

 private:
  void* m_originalThisPtr;
  int m_i;
};

TEST(VectorTest, SwapWithInlineCapacity) {
  const size_t inlineCapacity = 2;
  Vector<WrappedInt, inlineCapacity> vectorA;
  vectorA.push_back(WrappedInt(1));
  Vector<WrappedInt, inlineCapacity> vectorB;
  vectorB.push_back(WrappedInt(2));

  EXPECT_EQ(vectorA.size(), vectorB.size());
  vectorA.swap(vectorB);

  EXPECT_EQ(1u, vectorA.size());
  EXPECT_EQ(2, vectorA.at(0).get());
  EXPECT_EQ(1u, vectorB.size());
  EXPECT_EQ(1, vectorB.at(0).get());

  vectorA.push_back(WrappedInt(3));

  EXPECT_GT(vectorA.size(), vectorB.size());
  vectorA.swap(vectorB);

  EXPECT_EQ(1u, vectorA.size());
  EXPECT_EQ(1, vectorA.at(0).get());
  EXPECT_EQ(2u, vectorB.size());
  EXPECT_EQ(2, vectorB.at(0).get());
  EXPECT_EQ(3, vectorB.at(1).get());

  EXPECT_LT(vectorA.size(), vectorB.size());
  vectorA.swap(vectorB);

  EXPECT_EQ(2u, vectorA.size());
  EXPECT_EQ(2, vectorA.at(0).get());
  EXPECT_EQ(3, vectorA.at(1).get());
  EXPECT_EQ(1u, vectorB.size());
  EXPECT_EQ(1, vectorB.at(0).get());

  vectorA.push_back(WrappedInt(4));
  EXPECT_GT(vectorA.size(), inlineCapacity);
  vectorA.swap(vectorB);

  EXPECT_EQ(1u, vectorA.size());
  EXPECT_EQ(1, vectorA.at(0).get());
  EXPECT_EQ(3u, vectorB.size());
  EXPECT_EQ(2, vectorB.at(0).get());
  EXPECT_EQ(3, vectorB.at(1).get());
  EXPECT_EQ(4, vectorB.at(2).get());

  vectorB.swap(vectorA);
}

#if defined(ANNOTATE_CONTIGUOUS_CONTAINER)
TEST(VectorTest, ContainerAnnotations) {
  Vector<int> vectorA;
  vectorA.push_back(10);
  vectorA.reserveCapacity(32);

  volatile int* intPointerA = vectorA.data();
  EXPECT_DEATH(intPointerA[1] = 11, "container-overflow");
  vectorA.push_back(11);
  intPointerA[1] = 11;
  EXPECT_DEATH(intPointerA[2] = 12, "container-overflow");
  EXPECT_DEATH((void)intPointerA[2], "container-overflow");
  vectorA.shrinkToFit();
  vectorA.reserveCapacity(16);
  intPointerA = vectorA.data();
  EXPECT_DEATH((void)intPointerA[2], "container-overflow");

  Vector<int> vectorB(vectorA);
  vectorB.reserveCapacity(16);
  volatile int* intPointerB = vectorB.data();
  EXPECT_DEATH((void)intPointerB[2], "container-overflow");

  Vector<int> vectorC((Vector<int>(vectorA)));
  volatile int* intPointerC = vectorC.data();
  EXPECT_DEATH((void)intPointerC[2], "container-overflow");
  vectorC.push_back(13);
  vectorC.swap(vectorB);

  volatile int* intPointerB2 = vectorB.data();
  volatile int* intPointerC2 = vectorC.data();
  intPointerB2[2] = 13;
  EXPECT_DEATH((void)intPointerB2[3], "container-overflow");
  EXPECT_DEATH((void)intPointerC2[2], "container-overflow");

  vectorB = vectorC;
  volatile int* intPointerB3 = vectorB.data();
  EXPECT_DEATH((void)intPointerB3[2], "container-overflow");
}
#endif  // defined(ANNOTATE_CONTIGUOUS_CONTAINER)

class Comparable {};
bool operator==(const Comparable& a, const Comparable& b) {
  return true;
}

template <typename T>
void compare() {
  EXPECT_TRUE(Vector<T>() == Vector<T>());
  EXPECT_FALSE(Vector<T>(1) == Vector<T>(0));
  EXPECT_FALSE(Vector<T>() == Vector<T>(1));
  EXPECT_TRUE(Vector<T>(1) == Vector<T>(1));

  Vector<T, 1> vectorWithInlineCapacity;
  EXPECT_TRUE(vectorWithInlineCapacity == Vector<T>());
  EXPECT_FALSE(vectorWithInlineCapacity == Vector<T>(1));
}

TEST(VectorTest, Compare) {
  compare<int>();
  compare<Comparable>();
  compare<WTF::String>();
}

TEST(VectorTest, AppendFirst) {
  Vector<WTF::String> vector;
  vector.push_back("string");
  // Test passes if it does not crash (reallocation did not make
  // the input reference stale).
  size_t limit = vector.capacity() + 1;
  for (size_t i = 0; i < limit; i++)
    vector.push_back(vector.front());

  limit = vector.capacity() + 1;
  for (size_t i = 0; i < limit; i++)
    vector.push_back(const_cast<const WTF::String&>(vector.front()));
}

// The test below is for the following issue:
//
// https://bugs.chromium.org/p/chromium/issues/detail?id=592767
//
// where deleted copy assignment operator made canMoveWithMemcpy true because
// of the implementation of IsTriviallyMoveAssignable<T>.

class MojoMoveOnlyType final {
 public:
  MojoMoveOnlyType();
  MojoMoveOnlyType(MojoMoveOnlyType&&);
  MojoMoveOnlyType& operator=(MojoMoveOnlyType&&);
  ~MojoMoveOnlyType();

 private:
  MojoMoveOnlyType(const MojoMoveOnlyType&) = delete;
  void operator=(const MojoMoveOnlyType&) = delete;
};

static_assert(!IsTriviallyMoveAssignable<MojoMoveOnlyType>::value,
              "MojoMoveOnlyType isn't trivially move assignable.");
static_assert(!IsTriviallyCopyAssignable<MojoMoveOnlyType>::value,
              "MojoMoveOnlyType isn't trivially copy assignable.");

static_assert(!VectorTraits<MojoMoveOnlyType>::canMoveWithMemcpy,
              "MojoMoveOnlyType can't be moved with memcpy.");
static_assert(!VectorTraits<MojoMoveOnlyType>::canCopyWithMemcpy,
              "MojoMoveOnlyType can't be copied with memcpy.");

class LivenessCounter {
 public:
  void ref() { s_live++; }
  void deref() { s_live--; }

  static unsigned s_live;
};

unsigned LivenessCounter::s_live = 0;

class VectorWithDifferingInlineCapacityTest
    : public ::testing::TestWithParam<size_t> {};

template <size_t inlineCapacity>
void testDestructorAndConstructorCallsWhenSwappingWithInlineCapacity() {
  LivenessCounter::s_live = 0;
  LivenessCounter counter;
  EXPECT_EQ(0u, LivenessCounter::s_live);

  Vector<RefPtr<LivenessCounter>, inlineCapacity> vector;
  Vector<RefPtr<LivenessCounter>, inlineCapacity> vector2;
  vector.push_back(&counter);
  vector2.push_back(&counter);
  EXPECT_EQ(2u, LivenessCounter::s_live);

  for (unsigned i = 0; i < 13; i++) {
    for (unsigned j = 0; j < 13; j++) {
      vector.clear();
      vector2.clear();
      EXPECT_EQ(0u, LivenessCounter::s_live);

      for (unsigned k = 0; k < j; k++)
        vector.push_back(&counter);
      EXPECT_EQ(j, LivenessCounter::s_live);
      EXPECT_EQ(j, vector.size());

      for (unsigned k = 0; k < i; k++)
        vector2.push_back(&counter);
      EXPECT_EQ(i + j, LivenessCounter::s_live);
      EXPECT_EQ(i, vector2.size());

      vector.swap(vector2);
      EXPECT_EQ(i + j, LivenessCounter::s_live);
      EXPECT_EQ(i, vector.size());
      EXPECT_EQ(j, vector2.size());

      unsigned size = vector.size();
      unsigned size2 = vector2.size();

      for (unsigned k = 0; k < 5; k++) {
        vector.swap(vector2);
        std::swap(size, size2);
        EXPECT_EQ(i + j, LivenessCounter::s_live);
        EXPECT_EQ(size, vector.size());
        EXPECT_EQ(size2, vector2.size());

        vector2.push_back(&counter);
        vector2.remove(0);
      }
    }
  }
}

TEST(VectorTest, SwapWithConstructorsAndDestructors) {
  testDestructorAndConstructorCallsWhenSwappingWithInlineCapacity<0>();
  testDestructorAndConstructorCallsWhenSwappingWithInlineCapacity<2>();
  testDestructorAndConstructorCallsWhenSwappingWithInlineCapacity<10>();
}

template <size_t inlineCapacity>
void testValuesMovedAndSwappedWithInlineCapacity() {
  Vector<unsigned, inlineCapacity> vector;
  Vector<unsigned, inlineCapacity> vector2;

  for (unsigned size = 0; size < 13; size++) {
    for (unsigned size2 = 0; size2 < 13; size2++) {
      vector.clear();
      vector2.clear();
      for (unsigned i = 0; i < size; i++)
        vector.push_back(i);
      for (unsigned i = 0; i < size2; i++)
        vector2.push_back(i + 42);
      EXPECT_EQ(size, vector.size());
      EXPECT_EQ(size2, vector2.size());
      vector.swap(vector2);
      for (unsigned i = 0; i < size; i++)
        EXPECT_EQ(i, vector2[i]);
      for (unsigned i = 0; i < size2; i++)
        EXPECT_EQ(i + 42, vector[i]);
    }
  }
}

TEST(VectorTest, ValuesMovedAndSwappedWithInlineCapacity) {
  testValuesMovedAndSwappedWithInlineCapacity<0>();
  testValuesMovedAndSwappedWithInlineCapacity<2>();
  testValuesMovedAndSwappedWithInlineCapacity<10>();
}

TEST(VectorTest, UniquePtr) {
  using Pointer = std::unique_ptr<int>;
  Vector<Pointer> vector;
  vector.push_back(Pointer(new int(1)));
  vector.reserveCapacity(2);
  vector.uncheckedAppend(Pointer(new int(2)));
  vector.insert(2, Pointer(new int(3)));
  vector.push_front(Pointer(new int(0)));

  ASSERT_EQ(4u, vector.size());
  EXPECT_EQ(0, *vector[0]);
  EXPECT_EQ(1, *vector[1]);
  EXPECT_EQ(2, *vector[2]);
  EXPECT_EQ(3, *vector[3]);

  vector.shrink(3);
  EXPECT_EQ(3u, vector.size());
  vector.grow(4);
  ASSERT_EQ(4u, vector.size());
  EXPECT_TRUE(!vector[3]);
  vector.remove(3);
  vector[0] = Pointer(new int(-1));
  ASSERT_EQ(3u, vector.size());
  EXPECT_EQ(-1, *vector[0]);
}

bool isOneTwoThree(const Vector<int>& vector) {
  return vector.size() == 3 && vector[0] == 1 && vector[1] == 2 &&
         vector[2] == 3;
}

Vector<int> returnOneTwoThree() {
  return {1, 2, 3};
}

TEST(VectorTest, InitializerList) {
  Vector<int> empty({});
  EXPECT_TRUE(empty.isEmpty());

  Vector<int> one({1});
  ASSERT_EQ(1u, one.size());
  EXPECT_EQ(1, one[0]);

  Vector<int> oneTwoThree({1, 2, 3});
  ASSERT_EQ(3u, oneTwoThree.size());
  EXPECT_EQ(1, oneTwoThree[0]);
  EXPECT_EQ(2, oneTwoThree[1]);
  EXPECT_EQ(3, oneTwoThree[2]);

  // Put some jank so we can check if the assignments later can clear them.
  empty.push_back(9999);
  one.push_back(9999);
  oneTwoThree.push_back(9999);

  empty = {};
  EXPECT_TRUE(empty.isEmpty());

  one = {1};
  ASSERT_EQ(1u, one.size());
  EXPECT_EQ(1, one[0]);

  oneTwoThree = {1, 2, 3};
  ASSERT_EQ(3u, oneTwoThree.size());
  EXPECT_EQ(1, oneTwoThree[0]);
  EXPECT_EQ(2, oneTwoThree[1]);
  EXPECT_EQ(3, oneTwoThree[2]);

  // Other ways of construction: as a function parameter and in a return
  // statement.
  EXPECT_TRUE(isOneTwoThree({1, 2, 3}));
  EXPECT_TRUE(isOneTwoThree(returnOneTwoThree()));

  // The tests below correspond to the cases in the "if" branch in
  // operator=(std::initializer_list<T>).

  // Shrinking.
  Vector<int, 1> vector1(3);  // capacity = 3.
  vector1 = {1, 2};
  ASSERT_EQ(2u, vector1.size());
  EXPECT_EQ(1, vector1[0]);
  EXPECT_EQ(2, vector1[1]);

  // Expanding.
  Vector<int, 1> vector2(3);
  vector2 = {1, 2, 3, 4};
  ASSERT_EQ(4u, vector2.size());
  EXPECT_EQ(1, vector2[0]);
  EXPECT_EQ(2, vector2[1]);
  EXPECT_EQ(3, vector2[2]);
  EXPECT_EQ(4, vector2[3]);

  // Exact match.
  Vector<int, 1> vector3(3);
  vector3 = {1, 2, 3};
  ASSERT_EQ(3u, vector3.size());
  EXPECT_EQ(1, vector3[0]);
  EXPECT_EQ(2, vector3[1]);
  EXPECT_EQ(3, vector3[2]);
}

TEST(VectorTest, Optional) {
  Optional<Vector<int>> vector;
  EXPECT_FALSE(vector);
  vector.emplace(3);
  EXPECT_TRUE(vector);
  EXPECT_EQ(3u, vector->size());
}

TEST(VectorTest, emplace_back) {
  struct Item {
    Item() = default;
    explicit Item(int value1) : value1(value1), value2() {}
    Item(int value1, int value2) : value1(value1), value2(value2) {}
    int value1;
    int value2;
  };

  Vector<Item> vector;
  vector.emplace_back(1, 2);
  vector.emplace_back(3, 4);
  vector.emplace_back(5);
  vector.emplace_back();

  EXPECT_EQ(4u, vector.size());

  EXPECT_EQ(1, vector[0].value1);
  EXPECT_EQ(2, vector[0].value2);

  EXPECT_EQ(3, vector[1].value1);
  EXPECT_EQ(4, vector[1].value2);

  EXPECT_EQ(5, vector[2].value1);
  EXPECT_EQ(0, vector[2].value2);

  EXPECT_EQ(0, vector[3].value1);
  EXPECT_EQ(0, vector[3].value2);

  // Test returned value.
  Item& item = vector.emplace_back(6, 7);
  EXPECT_EQ(6, item.value1);
  EXPECT_EQ(7, item.value2);
}

static_assert(VectorTraits<int>::canCopyWithMemcpy,
              "int should be copied with memcopy.");
static_assert(VectorTraits<char>::canCopyWithMemcpy,
              "char should be copied with memcpy.");
static_assert(VectorTraits<LChar>::canCopyWithMemcpy,
              "LChar should be copied with memcpy.");
static_assert(VectorTraits<UChar>::canCopyWithMemcpy,
              "UChar should be copied with memcpy.");

class UnknownType;
static_assert(VectorTraits<UnknownType*>::canCopyWithMemcpy,
              "Pointers should be copied with memcpy.");

}  // anonymous namespace

}  // namespace WTF