llvm-for-llvmta/unittests/ADT/SmallVectorTest.cpp

1414 lines
43 KiB
C++

//===- llvm/unittest/ADT/SmallVectorTest.cpp ------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// SmallVector unit tests.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/Support/Compiler.h"
#include "gtest/gtest.h"
#include <list>
#include <stdarg.h>
using namespace llvm;
namespace {
/// A helper class that counts the total number of constructor and
/// destructor calls.
class Constructable {
private:
static int numConstructorCalls;
static int numMoveConstructorCalls;
static int numCopyConstructorCalls;
static int numDestructorCalls;
static int numAssignmentCalls;
static int numMoveAssignmentCalls;
static int numCopyAssignmentCalls;
bool constructed;
int value;
public:
Constructable() : constructed(true), value(0) {
++numConstructorCalls;
}
Constructable(int val) : constructed(true), value(val) {
++numConstructorCalls;
}
Constructable(const Constructable & src) : constructed(true) {
value = src.value;
++numConstructorCalls;
++numCopyConstructorCalls;
}
Constructable(Constructable && src) : constructed(true) {
value = src.value;
src.value = 0;
++numConstructorCalls;
++numMoveConstructorCalls;
}
~Constructable() {
EXPECT_TRUE(constructed);
++numDestructorCalls;
constructed = false;
}
Constructable & operator=(const Constructable & src) {
EXPECT_TRUE(constructed);
value = src.value;
++numAssignmentCalls;
++numCopyAssignmentCalls;
return *this;
}
Constructable & operator=(Constructable && src) {
EXPECT_TRUE(constructed);
value = src.value;
src.value = 0;
++numAssignmentCalls;
++numMoveAssignmentCalls;
return *this;
}
int getValue() const {
return abs(value);
}
static void reset() {
numConstructorCalls = 0;
numMoveConstructorCalls = 0;
numCopyConstructorCalls = 0;
numDestructorCalls = 0;
numAssignmentCalls = 0;
numMoveAssignmentCalls = 0;
numCopyAssignmentCalls = 0;
}
static int getNumConstructorCalls() {
return numConstructorCalls;
}
static int getNumMoveConstructorCalls() {
return numMoveConstructorCalls;
}
static int getNumCopyConstructorCalls() {
return numCopyConstructorCalls;
}
static int getNumDestructorCalls() {
return numDestructorCalls;
}
static int getNumAssignmentCalls() {
return numAssignmentCalls;
}
static int getNumMoveAssignmentCalls() {
return numMoveAssignmentCalls;
}
static int getNumCopyAssignmentCalls() {
return numCopyAssignmentCalls;
}
friend bool operator==(const Constructable & c0, const Constructable & c1) {
return c0.getValue() == c1.getValue();
}
friend bool LLVM_ATTRIBUTE_UNUSED
operator!=(const Constructable & c0, const Constructable & c1) {
return c0.getValue() != c1.getValue();
}
};
int Constructable::numConstructorCalls;
int Constructable::numCopyConstructorCalls;
int Constructable::numMoveConstructorCalls;
int Constructable::numDestructorCalls;
int Constructable::numAssignmentCalls;
int Constructable::numCopyAssignmentCalls;
int Constructable::numMoveAssignmentCalls;
struct NonCopyable {
NonCopyable() {}
NonCopyable(NonCopyable &&) {}
NonCopyable &operator=(NonCopyable &&) { return *this; }
private:
NonCopyable(const NonCopyable &) = delete;
NonCopyable &operator=(const NonCopyable &) = delete;
};
LLVM_ATTRIBUTE_USED void CompileTest() {
SmallVector<NonCopyable, 0> V;
V.resize(42);
}
class SmallVectorTestBase : public testing::Test {
protected:
void SetUp() override { Constructable::reset(); }
template <typename VectorT>
void assertEmpty(VectorT & v) {
// Size tests
EXPECT_EQ(0u, v.size());
EXPECT_TRUE(v.empty());
// Iterator tests
EXPECT_TRUE(v.begin() == v.end());
}
// Assert that v contains the specified values, in order.
template <typename VectorT>
void assertValuesInOrder(VectorT & v, size_t size, ...) {
EXPECT_EQ(size, v.size());
va_list ap;
va_start(ap, size);
for (size_t i = 0; i < size; ++i) {
int value = va_arg(ap, int);
EXPECT_EQ(value, v[i].getValue());
}
va_end(ap);
}
// Generate a sequence of values to initialize the vector.
template <typename VectorT>
void makeSequence(VectorT & v, int start, int end) {
for (int i = start; i <= end; ++i) {
v.push_back(Constructable(i));
}
}
};
// Test fixture class
template <typename VectorT>
class SmallVectorTest : public SmallVectorTestBase {
protected:
VectorT theVector;
VectorT otherVector;
};
typedef ::testing::Types<SmallVector<Constructable, 0>,
SmallVector<Constructable, 1>,
SmallVector<Constructable, 2>,
SmallVector<Constructable, 4>,
SmallVector<Constructable, 5>
> SmallVectorTestTypes;
TYPED_TEST_CASE(SmallVectorTest, SmallVectorTestTypes);
// Constructor test.
TYPED_TEST(SmallVectorTest, ConstructorNonIterTest) {
SCOPED_TRACE("ConstructorTest");
this->theVector = SmallVector<Constructable, 2>(2, 2);
this->assertValuesInOrder(this->theVector, 2u, 2, 2);
}
// Constructor test.
TYPED_TEST(SmallVectorTest, ConstructorIterTest) {
SCOPED_TRACE("ConstructorTest");
int arr[] = {1, 2, 3};
this->theVector =
SmallVector<Constructable, 4>(std::begin(arr), std::end(arr));
this->assertValuesInOrder(this->theVector, 3u, 1, 2, 3);
}
// New vector test.
TYPED_TEST(SmallVectorTest, EmptyVectorTest) {
SCOPED_TRACE("EmptyVectorTest");
this->assertEmpty(this->theVector);
EXPECT_TRUE(this->theVector.rbegin() == this->theVector.rend());
EXPECT_EQ(0, Constructable::getNumConstructorCalls());
EXPECT_EQ(0, Constructable::getNumDestructorCalls());
}
// Simple insertions and deletions.
TYPED_TEST(SmallVectorTest, PushPopTest) {
SCOPED_TRACE("PushPopTest");
// Track whether the vector will potentially have to grow.
bool RequiresGrowth = this->theVector.capacity() < 3;
// Push an element
this->theVector.push_back(Constructable(1));
// Size tests
this->assertValuesInOrder(this->theVector, 1u, 1);
EXPECT_FALSE(this->theVector.begin() == this->theVector.end());
EXPECT_FALSE(this->theVector.empty());
// Push another element
this->theVector.push_back(Constructable(2));
this->assertValuesInOrder(this->theVector, 2u, 1, 2);
// Insert at beginning. Reserve space to avoid reference invalidation from
// this->theVector[1].
this->theVector.reserve(this->theVector.size() + 1);
this->theVector.insert(this->theVector.begin(), this->theVector[1]);
this->assertValuesInOrder(this->theVector, 3u, 2, 1, 2);
// Pop one element
this->theVector.pop_back();
this->assertValuesInOrder(this->theVector, 2u, 2, 1);
// Pop remaining elements
this->theVector.pop_back_n(2);
this->assertEmpty(this->theVector);
// Check number of constructor calls. Should be 2 for each list element,
// one for the argument to push_back, one for the argument to insert,
// and one for the list element itself.
if (!RequiresGrowth) {
EXPECT_EQ(5, Constructable::getNumConstructorCalls());
EXPECT_EQ(5, Constructable::getNumDestructorCalls());
} else {
// If we had to grow the vector, these only have a lower bound, but should
// always be equal.
EXPECT_LE(5, Constructable::getNumConstructorCalls());
EXPECT_EQ(Constructable::getNumConstructorCalls(),
Constructable::getNumDestructorCalls());
}
}
// Clear test.
TYPED_TEST(SmallVectorTest, ClearTest) {
SCOPED_TRACE("ClearTest");
this->theVector.reserve(2);
this->makeSequence(this->theVector, 1, 2);
this->theVector.clear();
this->assertEmpty(this->theVector);
EXPECT_EQ(4, Constructable::getNumConstructorCalls());
EXPECT_EQ(4, Constructable::getNumDestructorCalls());
}
// Resize smaller test.
TYPED_TEST(SmallVectorTest, ResizeShrinkTest) {
SCOPED_TRACE("ResizeShrinkTest");
this->theVector.reserve(3);
this->makeSequence(this->theVector, 1, 3);
this->theVector.resize(1);
this->assertValuesInOrder(this->theVector, 1u, 1);
EXPECT_EQ(6, Constructable::getNumConstructorCalls());
EXPECT_EQ(5, Constructable::getNumDestructorCalls());
}
// Resize bigger test.
TYPED_TEST(SmallVectorTest, ResizeGrowTest) {
SCOPED_TRACE("ResizeGrowTest");
this->theVector.resize(2);
EXPECT_EQ(2, Constructable::getNumConstructorCalls());
EXPECT_EQ(0, Constructable::getNumDestructorCalls());
EXPECT_EQ(2u, this->theVector.size());
}
TYPED_TEST(SmallVectorTest, ResizeWithElementsTest) {
this->theVector.resize(2);
Constructable::reset();
this->theVector.resize(4);
size_t Ctors = Constructable::getNumConstructorCalls();
EXPECT_TRUE(Ctors == 2 || Ctors == 4);
size_t MoveCtors = Constructable::getNumMoveConstructorCalls();
EXPECT_TRUE(MoveCtors == 0 || MoveCtors == 2);
size_t Dtors = Constructable::getNumDestructorCalls();
EXPECT_TRUE(Dtors == 0 || Dtors == 2);
}
// Resize with fill value.
TYPED_TEST(SmallVectorTest, ResizeFillTest) {
SCOPED_TRACE("ResizeFillTest");
this->theVector.resize(3, Constructable(77));
this->assertValuesInOrder(this->theVector, 3u, 77, 77, 77);
}
TEST(SmallVectorTest, ResizeForOverwrite) {
{
// Heap allocated storage.
SmallVector<unsigned, 0> V;
V.push_back(5U);
V.pop_back();
V.resize_for_overwrite(V.size() + 1U);
EXPECT_EQ(5U, V.back());
V.pop_back();
V.resize(V.size() + 1);
EXPECT_EQ(0U, V.back());
}
{
// Inline storage.
SmallVector<unsigned, 2> V;
V.push_back(5U);
V.pop_back();
V.resize_for_overwrite(V.size() + 1U);
EXPECT_EQ(5U, V.back());
V.pop_back();
V.resize(V.size() + 1);
EXPECT_EQ(0U, V.back());
}
}
// Overflow past fixed size.
TYPED_TEST(SmallVectorTest, OverflowTest) {
SCOPED_TRACE("OverflowTest");
// Push more elements than the fixed size.
this->makeSequence(this->theVector, 1, 10);
// Test size and values.
EXPECT_EQ(10u, this->theVector.size());
for (int i = 0; i < 10; ++i) {
EXPECT_EQ(i+1, this->theVector[i].getValue());
}
// Now resize back to fixed size.
this->theVector.resize(1);
this->assertValuesInOrder(this->theVector, 1u, 1);
}
// Iteration tests.
TYPED_TEST(SmallVectorTest, IterationTest) {
this->makeSequence(this->theVector, 1, 2);
// Forward Iteration
typename TypeParam::iterator it = this->theVector.begin();
EXPECT_TRUE(*it == this->theVector.front());
EXPECT_TRUE(*it == this->theVector[0]);
EXPECT_EQ(1, it->getValue());
++it;
EXPECT_TRUE(*it == this->theVector[1]);
EXPECT_TRUE(*it == this->theVector.back());
EXPECT_EQ(2, it->getValue());
++it;
EXPECT_TRUE(it == this->theVector.end());
--it;
EXPECT_TRUE(*it == this->theVector[1]);
EXPECT_EQ(2, it->getValue());
--it;
EXPECT_TRUE(*it == this->theVector[0]);
EXPECT_EQ(1, it->getValue());
// Reverse Iteration
typename TypeParam::reverse_iterator rit = this->theVector.rbegin();
EXPECT_TRUE(*rit == this->theVector[1]);
EXPECT_EQ(2, rit->getValue());
++rit;
EXPECT_TRUE(*rit == this->theVector[0]);
EXPECT_EQ(1, rit->getValue());
++rit;
EXPECT_TRUE(rit == this->theVector.rend());
--rit;
EXPECT_TRUE(*rit == this->theVector[0]);
EXPECT_EQ(1, rit->getValue());
--rit;
EXPECT_TRUE(*rit == this->theVector[1]);
EXPECT_EQ(2, rit->getValue());
}
// Swap test.
TYPED_TEST(SmallVectorTest, SwapTest) {
SCOPED_TRACE("SwapTest");
this->makeSequence(this->theVector, 1, 2);
std::swap(this->theVector, this->otherVector);
this->assertEmpty(this->theVector);
this->assertValuesInOrder(this->otherVector, 2u, 1, 2);
}
// Append test
TYPED_TEST(SmallVectorTest, AppendTest) {
SCOPED_TRACE("AppendTest");
this->makeSequence(this->otherVector, 2, 3);
this->theVector.push_back(Constructable(1));
this->theVector.append(this->otherVector.begin(), this->otherVector.end());
this->assertValuesInOrder(this->theVector, 3u, 1, 2, 3);
}
// Append repeated test
TYPED_TEST(SmallVectorTest, AppendRepeatedTest) {
SCOPED_TRACE("AppendRepeatedTest");
this->theVector.push_back(Constructable(1));
this->theVector.append(2, Constructable(77));
this->assertValuesInOrder(this->theVector, 3u, 1, 77, 77);
}
// Append test
TYPED_TEST(SmallVectorTest, AppendNonIterTest) {
SCOPED_TRACE("AppendRepeatedTest");
this->theVector.push_back(Constructable(1));
this->theVector.append(2, 7);
this->assertValuesInOrder(this->theVector, 3u, 1, 7, 7);
}
struct output_iterator {
typedef std::output_iterator_tag iterator_category;
typedef int value_type;
typedef int difference_type;
typedef value_type *pointer;
typedef value_type &reference;
operator int() { return 2; }
operator Constructable() { return 7; }
};
TYPED_TEST(SmallVectorTest, AppendRepeatedNonForwardIterator) {
SCOPED_TRACE("AppendRepeatedTest");
this->theVector.push_back(Constructable(1));
this->theVector.append(output_iterator(), output_iterator());
this->assertValuesInOrder(this->theVector, 3u, 1, 7, 7);
}
TYPED_TEST(SmallVectorTest, AppendSmallVector) {
SCOPED_TRACE("AppendSmallVector");
SmallVector<Constructable, 3> otherVector = {7, 7};
this->theVector.push_back(Constructable(1));
this->theVector.append(otherVector);
this->assertValuesInOrder(this->theVector, 3u, 1, 7, 7);
}
// Assign test
TYPED_TEST(SmallVectorTest, AssignTest) {
SCOPED_TRACE("AssignTest");
this->theVector.push_back(Constructable(1));
this->theVector.assign(2, Constructable(77));
this->assertValuesInOrder(this->theVector, 2u, 77, 77);
}
// Assign test
TYPED_TEST(SmallVectorTest, AssignRangeTest) {
SCOPED_TRACE("AssignTest");
this->theVector.push_back(Constructable(1));
int arr[] = {1, 2, 3};
this->theVector.assign(std::begin(arr), std::end(arr));
this->assertValuesInOrder(this->theVector, 3u, 1, 2, 3);
}
// Assign test
TYPED_TEST(SmallVectorTest, AssignNonIterTest) {
SCOPED_TRACE("AssignTest");
this->theVector.push_back(Constructable(1));
this->theVector.assign(2, 7);
this->assertValuesInOrder(this->theVector, 2u, 7, 7);
}
TYPED_TEST(SmallVectorTest, AssignSmallVector) {
SCOPED_TRACE("AssignSmallVector");
SmallVector<Constructable, 3> otherVector = {7, 7};
this->theVector.push_back(Constructable(1));
this->theVector.assign(otherVector);
this->assertValuesInOrder(this->theVector, 2u, 7, 7);
}
// Move-assign test
TYPED_TEST(SmallVectorTest, MoveAssignTest) {
SCOPED_TRACE("MoveAssignTest");
// Set up our vector with a single element, but enough capacity for 4.
this->theVector.reserve(4);
this->theVector.push_back(Constructable(1));
// Set up the other vector with 2 elements.
this->otherVector.push_back(Constructable(2));
this->otherVector.push_back(Constructable(3));
// Move-assign from the other vector.
this->theVector = std::move(this->otherVector);
// Make sure we have the right result.
this->assertValuesInOrder(this->theVector, 2u, 2, 3);
// Make sure the # of constructor/destructor calls line up. There
// are two live objects after clearing the other vector.
this->otherVector.clear();
EXPECT_EQ(Constructable::getNumConstructorCalls()-2,
Constructable::getNumDestructorCalls());
// There shouldn't be any live objects any more.
this->theVector.clear();
EXPECT_EQ(Constructable::getNumConstructorCalls(),
Constructable::getNumDestructorCalls());
}
// Erase a single element
TYPED_TEST(SmallVectorTest, EraseTest) {
SCOPED_TRACE("EraseTest");
this->makeSequence(this->theVector, 1, 3);
const auto &theConstVector = this->theVector;
this->theVector.erase(theConstVector.begin());
this->assertValuesInOrder(this->theVector, 2u, 2, 3);
}
// Erase a range of elements
TYPED_TEST(SmallVectorTest, EraseRangeTest) {
SCOPED_TRACE("EraseRangeTest");
this->makeSequence(this->theVector, 1, 3);
const auto &theConstVector = this->theVector;
this->theVector.erase(theConstVector.begin(), theConstVector.begin() + 2);
this->assertValuesInOrder(this->theVector, 1u, 3);
}
// Insert a single element.
TYPED_TEST(SmallVectorTest, InsertTest) {
SCOPED_TRACE("InsertTest");
this->makeSequence(this->theVector, 1, 3);
typename TypeParam::iterator I =
this->theVector.insert(this->theVector.begin() + 1, Constructable(77));
EXPECT_EQ(this->theVector.begin() + 1, I);
this->assertValuesInOrder(this->theVector, 4u, 1, 77, 2, 3);
}
// Insert a copy of a single element.
TYPED_TEST(SmallVectorTest, InsertCopy) {
SCOPED_TRACE("InsertTest");
this->makeSequence(this->theVector, 1, 3);
Constructable C(77);
typename TypeParam::iterator I =
this->theVector.insert(this->theVector.begin() + 1, C);
EXPECT_EQ(this->theVector.begin() + 1, I);
this->assertValuesInOrder(this->theVector, 4u, 1, 77, 2, 3);
}
// Insert repeated elements.
TYPED_TEST(SmallVectorTest, InsertRepeatedTest) {
SCOPED_TRACE("InsertRepeatedTest");
this->makeSequence(this->theVector, 1, 4);
Constructable::reset();
auto I =
this->theVector.insert(this->theVector.begin() + 1, 2, Constructable(16));
// Move construct the top element into newly allocated space, and optionally
// reallocate the whole buffer, move constructing into it.
// FIXME: This is inefficient, we shouldn't move things into newly allocated
// space, then move them up/around, there should only be 2 or 4 move
// constructions here.
EXPECT_TRUE(Constructable::getNumMoveConstructorCalls() == 2 ||
Constructable::getNumMoveConstructorCalls() == 6);
// Move assign the next two to shift them up and make a gap.
EXPECT_EQ(1, Constructable::getNumMoveAssignmentCalls());
// Copy construct the two new elements from the parameter.
EXPECT_EQ(2, Constructable::getNumCopyAssignmentCalls());
// All without any copy construction.
EXPECT_EQ(0, Constructable::getNumCopyConstructorCalls());
EXPECT_EQ(this->theVector.begin() + 1, I);
this->assertValuesInOrder(this->theVector, 6u, 1, 16, 16, 2, 3, 4);
}
TYPED_TEST(SmallVectorTest, InsertRepeatedNonIterTest) {
SCOPED_TRACE("InsertRepeatedTest");
this->makeSequence(this->theVector, 1, 4);
Constructable::reset();
auto I = this->theVector.insert(this->theVector.begin() + 1, 2, 7);
EXPECT_EQ(this->theVector.begin() + 1, I);
this->assertValuesInOrder(this->theVector, 6u, 1, 7, 7, 2, 3, 4);
}
TYPED_TEST(SmallVectorTest, InsertRepeatedAtEndTest) {
SCOPED_TRACE("InsertRepeatedTest");
this->makeSequence(this->theVector, 1, 4);
Constructable::reset();
auto I = this->theVector.insert(this->theVector.end(), 2, Constructable(16));
// Just copy construct them into newly allocated space
EXPECT_EQ(2, Constructable::getNumCopyConstructorCalls());
// Move everything across if reallocation is needed.
EXPECT_TRUE(Constructable::getNumMoveConstructorCalls() == 0 ||
Constructable::getNumMoveConstructorCalls() == 4);
// Without ever moving or copying anything else.
EXPECT_EQ(0, Constructable::getNumCopyAssignmentCalls());
EXPECT_EQ(0, Constructable::getNumMoveAssignmentCalls());
EXPECT_EQ(this->theVector.begin() + 4, I);
this->assertValuesInOrder(this->theVector, 6u, 1, 2, 3, 4, 16, 16);
}
TYPED_TEST(SmallVectorTest, InsertRepeatedEmptyTest) {
SCOPED_TRACE("InsertRepeatedTest");
this->makeSequence(this->theVector, 10, 15);
// Empty insert.
EXPECT_EQ(this->theVector.end(),
this->theVector.insert(this->theVector.end(),
0, Constructable(42)));
EXPECT_EQ(this->theVector.begin() + 1,
this->theVector.insert(this->theVector.begin() + 1,
0, Constructable(42)));
}
// Insert range.
TYPED_TEST(SmallVectorTest, InsertRangeTest) {
SCOPED_TRACE("InsertRangeTest");
Constructable Arr[3] =
{ Constructable(77), Constructable(77), Constructable(77) };
this->makeSequence(this->theVector, 1, 3);
Constructable::reset();
auto I = this->theVector.insert(this->theVector.begin() + 1, Arr, Arr + 3);
// Move construct the top 3 elements into newly allocated space.
// Possibly move the whole sequence into new space first.
// FIXME: This is inefficient, we shouldn't move things into newly allocated
// space, then move them up/around, there should only be 2 or 3 move
// constructions here.
EXPECT_TRUE(Constructable::getNumMoveConstructorCalls() == 2 ||
Constructable::getNumMoveConstructorCalls() == 5);
// Copy assign the lower 2 new elements into existing space.
EXPECT_EQ(2, Constructable::getNumCopyAssignmentCalls());
// Copy construct the third element into newly allocated space.
EXPECT_EQ(1, Constructable::getNumCopyConstructorCalls());
EXPECT_EQ(this->theVector.begin() + 1, I);
this->assertValuesInOrder(this->theVector, 6u, 1, 77, 77, 77, 2, 3);
}
TYPED_TEST(SmallVectorTest, InsertRangeAtEndTest) {
SCOPED_TRACE("InsertRangeTest");
Constructable Arr[3] =
{ Constructable(77), Constructable(77), Constructable(77) };
this->makeSequence(this->theVector, 1, 3);
// Insert at end.
Constructable::reset();
auto I = this->theVector.insert(this->theVector.end(), Arr, Arr+3);
// Copy construct the 3 elements into new space at the top.
EXPECT_EQ(3, Constructable::getNumCopyConstructorCalls());
// Don't copy/move anything else.
EXPECT_EQ(0, Constructable::getNumCopyAssignmentCalls());
// Reallocation might occur, causing all elements to be moved into the new
// buffer.
EXPECT_TRUE(Constructable::getNumMoveConstructorCalls() == 0 ||
Constructable::getNumMoveConstructorCalls() == 3);
EXPECT_EQ(0, Constructable::getNumMoveAssignmentCalls());
EXPECT_EQ(this->theVector.begin() + 3, I);
this->assertValuesInOrder(this->theVector, 6u,
1, 2, 3, 77, 77, 77);
}
TYPED_TEST(SmallVectorTest, InsertEmptyRangeTest) {
SCOPED_TRACE("InsertRangeTest");
this->makeSequence(this->theVector, 1, 3);
// Empty insert.
EXPECT_EQ(this->theVector.end(),
this->theVector.insert(this->theVector.end(),
this->theVector.begin(),
this->theVector.begin()));
EXPECT_EQ(this->theVector.begin() + 1,
this->theVector.insert(this->theVector.begin() + 1,
this->theVector.begin(),
this->theVector.begin()));
}
// Comparison tests.
TYPED_TEST(SmallVectorTest, ComparisonTest) {
SCOPED_TRACE("ComparisonTest");
this->makeSequence(this->theVector, 1, 3);
this->makeSequence(this->otherVector, 1, 3);
EXPECT_TRUE(this->theVector == this->otherVector);
EXPECT_FALSE(this->theVector != this->otherVector);
this->otherVector.clear();
this->makeSequence(this->otherVector, 2, 4);
EXPECT_FALSE(this->theVector == this->otherVector);
EXPECT_TRUE(this->theVector != this->otherVector);
}
// Constant vector tests.
TYPED_TEST(SmallVectorTest, ConstVectorTest) {
const TypeParam constVector;
EXPECT_EQ(0u, constVector.size());
EXPECT_TRUE(constVector.empty());
EXPECT_TRUE(constVector.begin() == constVector.end());
}
// Direct array access.
TYPED_TEST(SmallVectorTest, DirectVectorTest) {
EXPECT_EQ(0u, this->theVector.size());
this->theVector.reserve(4);
EXPECT_LE(4u, this->theVector.capacity());
EXPECT_EQ(0, Constructable::getNumConstructorCalls());
this->theVector.push_back(1);
this->theVector.push_back(2);
this->theVector.push_back(3);
this->theVector.push_back(4);
EXPECT_EQ(4u, this->theVector.size());
EXPECT_EQ(8, Constructable::getNumConstructorCalls());
EXPECT_EQ(1, this->theVector[0].getValue());
EXPECT_EQ(2, this->theVector[1].getValue());
EXPECT_EQ(3, this->theVector[2].getValue());
EXPECT_EQ(4, this->theVector[3].getValue());
}
TYPED_TEST(SmallVectorTest, IteratorTest) {
std::list<int> L;
this->theVector.insert(this->theVector.end(), L.begin(), L.end());
}
template <typename InvalidType> class DualSmallVectorsTest;
template <typename VectorT1, typename VectorT2>
class DualSmallVectorsTest<std::pair<VectorT1, VectorT2>> : public SmallVectorTestBase {
protected:
VectorT1 theVector;
VectorT2 otherVector;
template <typename T, unsigned N>
static unsigned NumBuiltinElts(const SmallVector<T, N>&) { return N; }
};
typedef ::testing::Types<
// Small mode -> Small mode.
std::pair<SmallVector<Constructable, 4>, SmallVector<Constructable, 4>>,
// Small mode -> Big mode.
std::pair<SmallVector<Constructable, 4>, SmallVector<Constructable, 2>>,
// Big mode -> Small mode.
std::pair<SmallVector<Constructable, 2>, SmallVector<Constructable, 4>>,
// Big mode -> Big mode.
std::pair<SmallVector<Constructable, 2>, SmallVector<Constructable, 2>>
> DualSmallVectorTestTypes;
TYPED_TEST_CASE(DualSmallVectorsTest, DualSmallVectorTestTypes);
TYPED_TEST(DualSmallVectorsTest, MoveAssignment) {
SCOPED_TRACE("MoveAssignTest-DualVectorTypes");
// Set up our vector with four elements.
for (unsigned I = 0; I < 4; ++I)
this->otherVector.push_back(Constructable(I));
const Constructable *OrigDataPtr = this->otherVector.data();
// Move-assign from the other vector.
this->theVector =
std::move(static_cast<SmallVectorImpl<Constructable>&>(this->otherVector));
// Make sure we have the right result.
this->assertValuesInOrder(this->theVector, 4u, 0, 1, 2, 3);
// Make sure the # of constructor/destructor calls line up. There
// are two live objects after clearing the other vector.
this->otherVector.clear();
EXPECT_EQ(Constructable::getNumConstructorCalls()-4,
Constructable::getNumDestructorCalls());
// If the source vector (otherVector) was in small-mode, assert that we just
// moved the data pointer over.
EXPECT_TRUE(this->NumBuiltinElts(this->otherVector) == 4 ||
this->theVector.data() == OrigDataPtr);
// There shouldn't be any live objects any more.
this->theVector.clear();
EXPECT_EQ(Constructable::getNumConstructorCalls(),
Constructable::getNumDestructorCalls());
// We shouldn't have copied anything in this whole process.
EXPECT_EQ(Constructable::getNumCopyConstructorCalls(), 0);
}
struct notassignable {
int &x;
notassignable(int &x) : x(x) {}
};
TEST(SmallVectorCustomTest, NoAssignTest) {
int x = 0;
SmallVector<notassignable, 2> vec;
vec.push_back(notassignable(x));
x = 42;
EXPECT_EQ(42, vec.pop_back_val().x);
}
struct MovedFrom {
bool hasValue;
MovedFrom() : hasValue(true) {
}
MovedFrom(MovedFrom&& m) : hasValue(m.hasValue) {
m.hasValue = false;
}
MovedFrom &operator=(MovedFrom&& m) {
hasValue = m.hasValue;
m.hasValue = false;
return *this;
}
};
TEST(SmallVectorTest, MidInsert) {
SmallVector<MovedFrom, 3> v;
v.push_back(MovedFrom());
v.insert(v.begin(), MovedFrom());
for (MovedFrom &m : v)
EXPECT_TRUE(m.hasValue);
}
enum EmplaceableArgState {
EAS_Defaulted,
EAS_Arg,
EAS_LValue,
EAS_RValue,
EAS_Failure
};
template <int I> struct EmplaceableArg {
EmplaceableArgState State;
EmplaceableArg() : State(EAS_Defaulted) {}
EmplaceableArg(EmplaceableArg &&X)
: State(X.State == EAS_Arg ? EAS_RValue : EAS_Failure) {}
EmplaceableArg(EmplaceableArg &X)
: State(X.State == EAS_Arg ? EAS_LValue : EAS_Failure) {}
explicit EmplaceableArg(bool) : State(EAS_Arg) {}
private:
EmplaceableArg &operator=(EmplaceableArg &&) = delete;
EmplaceableArg &operator=(const EmplaceableArg &) = delete;
};
enum EmplaceableState { ES_Emplaced, ES_Moved };
struct Emplaceable {
EmplaceableArg<0> A0;
EmplaceableArg<1> A1;
EmplaceableArg<2> A2;
EmplaceableArg<3> A3;
EmplaceableState State;
Emplaceable() : State(ES_Emplaced) {}
template <class A0Ty>
explicit Emplaceable(A0Ty &&A0)
: A0(std::forward<A0Ty>(A0)), State(ES_Emplaced) {}
template <class A0Ty, class A1Ty>
Emplaceable(A0Ty &&A0, A1Ty &&A1)
: A0(std::forward<A0Ty>(A0)), A1(std::forward<A1Ty>(A1)),
State(ES_Emplaced) {}
template <class A0Ty, class A1Ty, class A2Ty>
Emplaceable(A0Ty &&A0, A1Ty &&A1, A2Ty &&A2)
: A0(std::forward<A0Ty>(A0)), A1(std::forward<A1Ty>(A1)),
A2(std::forward<A2Ty>(A2)), State(ES_Emplaced) {}
template <class A0Ty, class A1Ty, class A2Ty, class A3Ty>
Emplaceable(A0Ty &&A0, A1Ty &&A1, A2Ty &&A2, A3Ty &&A3)
: A0(std::forward<A0Ty>(A0)), A1(std::forward<A1Ty>(A1)),
A2(std::forward<A2Ty>(A2)), A3(std::forward<A3Ty>(A3)),
State(ES_Emplaced) {}
Emplaceable(Emplaceable &&) : State(ES_Moved) {}
Emplaceable &operator=(Emplaceable &&) {
State = ES_Moved;
return *this;
}
private:
Emplaceable(const Emplaceable &) = delete;
Emplaceable &operator=(const Emplaceable &) = delete;
};
TEST(SmallVectorTest, EmplaceBack) {
EmplaceableArg<0> A0(true);
EmplaceableArg<1> A1(true);
EmplaceableArg<2> A2(true);
EmplaceableArg<3> A3(true);
{
SmallVector<Emplaceable, 3> V;
Emplaceable &back = V.emplace_back();
EXPECT_TRUE(&back == &V.back());
EXPECT_TRUE(V.size() == 1);
EXPECT_TRUE(back.State == ES_Emplaced);
EXPECT_TRUE(back.A0.State == EAS_Defaulted);
EXPECT_TRUE(back.A1.State == EAS_Defaulted);
EXPECT_TRUE(back.A2.State == EAS_Defaulted);
EXPECT_TRUE(back.A3.State == EAS_Defaulted);
}
{
SmallVector<Emplaceable, 3> V;
Emplaceable &back = V.emplace_back(std::move(A0));
EXPECT_TRUE(&back == &V.back());
EXPECT_TRUE(V.size() == 1);
EXPECT_TRUE(back.State == ES_Emplaced);
EXPECT_TRUE(back.A0.State == EAS_RValue);
EXPECT_TRUE(back.A1.State == EAS_Defaulted);
EXPECT_TRUE(back.A2.State == EAS_Defaulted);
EXPECT_TRUE(back.A3.State == EAS_Defaulted);
}
{
SmallVector<Emplaceable, 3> V;
Emplaceable &back = V.emplace_back(A0);
EXPECT_TRUE(&back == &V.back());
EXPECT_TRUE(V.size() == 1);
EXPECT_TRUE(back.State == ES_Emplaced);
EXPECT_TRUE(back.A0.State == EAS_LValue);
EXPECT_TRUE(back.A1.State == EAS_Defaulted);
EXPECT_TRUE(back.A2.State == EAS_Defaulted);
EXPECT_TRUE(back.A3.State == EAS_Defaulted);
}
{
SmallVector<Emplaceable, 3> V;
Emplaceable &back = V.emplace_back(A0, A1);
EXPECT_TRUE(&back == &V.back());
EXPECT_TRUE(V.size() == 1);
EXPECT_TRUE(back.State == ES_Emplaced);
EXPECT_TRUE(back.A0.State == EAS_LValue);
EXPECT_TRUE(back.A1.State == EAS_LValue);
EXPECT_TRUE(back.A2.State == EAS_Defaulted);
EXPECT_TRUE(back.A3.State == EAS_Defaulted);
}
{
SmallVector<Emplaceable, 3> V;
Emplaceable &back = V.emplace_back(std::move(A0), std::move(A1));
EXPECT_TRUE(&back == &V.back());
EXPECT_TRUE(V.size() == 1);
EXPECT_TRUE(back.State == ES_Emplaced);
EXPECT_TRUE(back.A0.State == EAS_RValue);
EXPECT_TRUE(back.A1.State == EAS_RValue);
EXPECT_TRUE(back.A2.State == EAS_Defaulted);
EXPECT_TRUE(back.A3.State == EAS_Defaulted);
}
{
SmallVector<Emplaceable, 3> V;
Emplaceable &back = V.emplace_back(std::move(A0), A1, std::move(A2), A3);
EXPECT_TRUE(&back == &V.back());
EXPECT_TRUE(V.size() == 1);
EXPECT_TRUE(back.State == ES_Emplaced);
EXPECT_TRUE(back.A0.State == EAS_RValue);
EXPECT_TRUE(back.A1.State == EAS_LValue);
EXPECT_TRUE(back.A2.State == EAS_RValue);
EXPECT_TRUE(back.A3.State == EAS_LValue);
}
{
SmallVector<int, 1> V;
V.emplace_back();
V.emplace_back(42);
EXPECT_EQ(2U, V.size());
EXPECT_EQ(0, V[0]);
EXPECT_EQ(42, V[1]);
}
}
TEST(SmallVectorTest, DefaultInlinedElements) {
SmallVector<int> V;
EXPECT_TRUE(V.empty());
V.push_back(7);
EXPECT_EQ(V[0], 7);
// Check that at least a couple layers of nested SmallVector<T>'s are allowed
// by the default inline elements policy. This pattern happens in practice
// with some frequency, and it seems fairly harmless even though each layer of
// SmallVector's will grow the total sizeof by a vector header beyond the
// "preferred" maximum sizeof.
SmallVector<SmallVector<SmallVector<int>>> NestedV;
NestedV.emplace_back().emplace_back().emplace_back(42);
EXPECT_EQ(NestedV[0][0][0], 42);
}
TEST(SmallVectorTest, InitializerList) {
SmallVector<int, 2> V1 = {};
EXPECT_TRUE(V1.empty());
V1 = {0, 0};
EXPECT_TRUE(makeArrayRef(V1).equals({0, 0}));
V1 = {-1, -1};
EXPECT_TRUE(makeArrayRef(V1).equals({-1, -1}));
SmallVector<int, 2> V2 = {1, 2, 3, 4};
EXPECT_TRUE(makeArrayRef(V2).equals({1, 2, 3, 4}));
V2.assign({4});
EXPECT_TRUE(makeArrayRef(V2).equals({4}));
V2.append({3, 2});
EXPECT_TRUE(makeArrayRef(V2).equals({4, 3, 2}));
V2.insert(V2.begin() + 1, 5);
EXPECT_TRUE(makeArrayRef(V2).equals({4, 5, 3, 2}));
}
template <class VectorT>
class SmallVectorReferenceInvalidationTest : public SmallVectorTestBase {
protected:
const char *AssertionMessage =
"Attempting to reference an element of the vector in an operation \" "
"\"that invalidates it";
VectorT V;
template <typename T, unsigned N>
static unsigned NumBuiltinElts(const SmallVector<T, N> &) {
return N;
}
template <class T> static bool isValueType() {
return std::is_same<T, typename VectorT::value_type>::value;
}
void SetUp() override {
SmallVectorTestBase::SetUp();
// Fill up the small size so that insertions move the elements.
for (int I = 0, E = NumBuiltinElts(V); I != E; ++I)
V.emplace_back(I + 1);
}
};
// Test one type that's trivially copyable (int) and one that isn't
// (Constructable) since reference invalidation may be fixed differently for
// each.
using SmallVectorReferenceInvalidationTestTypes =
::testing::Types<SmallVector<int, 3>, SmallVector<Constructable, 3>>;
TYPED_TEST_CASE(SmallVectorReferenceInvalidationTest,
SmallVectorReferenceInvalidationTestTypes);
TYPED_TEST(SmallVectorReferenceInvalidationTest, PushBack) {
// Note: setup adds [1, 2, ...] to V until it's at capacity in small mode.
auto &V = this->V;
int N = this->NumBuiltinElts(V);
// Push back a reference to last element when growing from small storage.
V.push_back(V.back());
EXPECT_EQ(N, V.back());
// Check that the old value is still there (not moved away).
EXPECT_EQ(N, V[V.size() - 2]);
// Fill storage again.
V.back() = V.size();
while (V.size() < V.capacity())
V.push_back(V.size() + 1);
// Push back a reference to last element when growing from large storage.
V.push_back(V.back());
EXPECT_EQ(int(V.size()) - 1, V.back());
}
TYPED_TEST(SmallVectorReferenceInvalidationTest, PushBackMoved) {
// Note: setup adds [1, 2, ...] to V until it's at capacity in small mode.
auto &V = this->V;
int N = this->NumBuiltinElts(V);
// Push back a reference to last element when growing from small storage.
V.push_back(std::move(V.back()));
EXPECT_EQ(N, V.back());
if (this->template isValueType<Constructable>()) {
// Check that the value was moved (not copied).
EXPECT_EQ(0, V[V.size() - 2]);
}
// Fill storage again.
V.back() = V.size();
while (V.size() < V.capacity())
V.push_back(V.size() + 1);
// Push back a reference to last element when growing from large storage.
V.push_back(std::move(V.back()));
// Check the values.
EXPECT_EQ(int(V.size()) - 1, V.back());
if (this->template isValueType<Constructable>()) {
// Check the value got moved out.
EXPECT_EQ(0, V[V.size() - 2]);
}
}
TYPED_TEST(SmallVectorReferenceInvalidationTest, Resize) {
auto &V = this->V;
(void)V;
int N = this->NumBuiltinElts(V);
V.resize(N + 1, V.back());
EXPECT_EQ(N, V.back());
// Resize to add enough elements that V will grow again. If reference
// invalidation breaks in the future, sanitizers should be able to catch a
// use-after-free here.
V.resize(V.capacity() + 1, V.front());
EXPECT_EQ(1, V.back());
}
TYPED_TEST(SmallVectorReferenceInvalidationTest, Append) {
auto &V = this->V;
(void)V;
V.append(1, V.back());
int N = this->NumBuiltinElts(V);
EXPECT_EQ(N, V[N - 1]);
// Append enough more elements that V will grow again. This tests growing
// when already in large mode.
//
// If reference invalidation breaks in the future, sanitizers should be able
// to catch a use-after-free here.
V.append(V.capacity() - V.size() + 1, V.front());
EXPECT_EQ(1, V.back());
}
TYPED_TEST(SmallVectorReferenceInvalidationTest, AppendRange) {
auto &V = this->V;
(void)V;
#if !defined(NDEBUG) && GTEST_HAS_DEATH_TEST
EXPECT_DEATH(V.append(V.begin(), V.begin() + 1), this->AssertionMessage);
ASSERT_EQ(3u, this->NumBuiltinElts(V));
ASSERT_EQ(3u, V.size());
V.pop_back();
ASSERT_EQ(2u, V.size());
// Confirm this checks for growth when there's more than one element
// appended.
EXPECT_DEATH(V.append(V.begin(), V.end()), this->AssertionMessage);
#endif
}
TYPED_TEST(SmallVectorReferenceInvalidationTest, Assign) {
// Note: setup adds [1, 2, ...] to V until it's at capacity in small mode.
auto &V = this->V;
(void)V;
int N = this->NumBuiltinElts(V);
ASSERT_EQ(unsigned(N), V.size());
ASSERT_EQ(unsigned(N), V.capacity());
// Check assign that shrinks in small mode.
V.assign(1, V.back());
EXPECT_EQ(1u, V.size());
EXPECT_EQ(N, V[0]);
// Check assign that grows within small mode.
ASSERT_LT(V.size(), V.capacity());
V.assign(V.capacity(), V.back());
for (int I = 0, E = V.size(); I != E; ++I) {
EXPECT_EQ(N, V[I]);
// Reset to [1, 2, ...].
V[I] = I + 1;
}
// Check assign that grows to large mode.
ASSERT_EQ(2, V[1]);
V.assign(V.capacity() + 1, V[1]);
for (int I = 0, E = V.size(); I != E; ++I) {
EXPECT_EQ(2, V[I]);
// Reset to [1, 2, ...].
V[I] = I + 1;
}
// Check assign that shrinks in large mode.
V.assign(1, V[1]);
EXPECT_EQ(2, V[0]);
}
TYPED_TEST(SmallVectorReferenceInvalidationTest, AssignRange) {
auto &V = this->V;
#if !defined(NDEBUG) && GTEST_HAS_DEATH_TEST
EXPECT_DEATH(V.assign(V.begin(), V.end()), this->AssertionMessage);
EXPECT_DEATH(V.assign(V.begin(), V.end() - 1), this->AssertionMessage);
#endif
V.assign(V.begin(), V.begin());
EXPECT_TRUE(V.empty());
}
TYPED_TEST(SmallVectorReferenceInvalidationTest, Insert) {
// Note: setup adds [1, 2, ...] to V until it's at capacity in small mode.
auto &V = this->V;
(void)V;
// Insert a reference to the back (not at end() or else insert delegates to
// push_back()), growing out of small mode. Confirm the value was copied out
// (moving out Constructable sets it to 0).
V.insert(V.begin(), V.back());
EXPECT_EQ(int(V.size() - 1), V.front());
EXPECT_EQ(int(V.size() - 1), V.back());
// Fill up the vector again.
while (V.size() < V.capacity())
V.push_back(V.size() + 1);
// Grow again from large storage to large storage.
V.insert(V.begin(), V.back());
EXPECT_EQ(int(V.size() - 1), V.front());
EXPECT_EQ(int(V.size() - 1), V.back());
}
TYPED_TEST(SmallVectorReferenceInvalidationTest, InsertMoved) {
// Note: setup adds [1, 2, ...] to V until it's at capacity in small mode.
auto &V = this->V;
(void)V;
// Insert a reference to the back (not at end() or else insert delegates to
// push_back()), growing out of small mode. Confirm the value was copied out
// (moving out Constructable sets it to 0).
V.insert(V.begin(), std::move(V.back()));
EXPECT_EQ(int(V.size() - 1), V.front());
if (this->template isValueType<Constructable>()) {
// Check the value got moved out.
EXPECT_EQ(0, V.back());
}
// Fill up the vector again.
while (V.size() < V.capacity())
V.push_back(V.size() + 1);
// Grow again from large storage to large storage.
V.insert(V.begin(), std::move(V.back()));
EXPECT_EQ(int(V.size() - 1), V.front());
if (this->template isValueType<Constructable>()) {
// Check the value got moved out.
EXPECT_EQ(0, V.back());
}
}
TYPED_TEST(SmallVectorReferenceInvalidationTest, InsertN) {
auto &V = this->V;
(void)V;
// Cover NumToInsert <= this->end() - I.
V.insert(V.begin() + 1, 1, V.back());
int N = this->NumBuiltinElts(V);
EXPECT_EQ(N, V[1]);
// Cover NumToInsert > this->end() - I, inserting enough elements that V will
// also grow again; V.capacity() will be more elements than necessary but
// it's a simple way to cover both conditions.
//
// If reference invalidation breaks in the future, sanitizers should be able
// to catch a use-after-free here.
V.insert(V.begin(), V.capacity(), V.front());
EXPECT_EQ(1, V.front());
}
TYPED_TEST(SmallVectorReferenceInvalidationTest, InsertRange) {
auto &V = this->V;
(void)V;
#if !defined(NDEBUG) && GTEST_HAS_DEATH_TEST
EXPECT_DEATH(V.insert(V.begin(), V.begin(), V.begin() + 1),
this->AssertionMessage);
ASSERT_EQ(3u, this->NumBuiltinElts(V));
ASSERT_EQ(3u, V.size());
V.pop_back();
ASSERT_EQ(2u, V.size());
// Confirm this checks for growth when there's more than one element
// inserted.
EXPECT_DEATH(V.insert(V.begin(), V.begin(), V.end()), this->AssertionMessage);
#endif
}
TYPED_TEST(SmallVectorReferenceInvalidationTest, EmplaceBack) {
// Note: setup adds [1, 2, ...] to V until it's at capacity in small mode.
auto &V = this->V;
int N = this->NumBuiltinElts(V);
// Push back a reference to last element when growing from small storage.
V.emplace_back(V.back());
EXPECT_EQ(N, V.back());
// Check that the old value is still there (not moved away).
EXPECT_EQ(N, V[V.size() - 2]);
// Fill storage again.
V.back() = V.size();
while (V.size() < V.capacity())
V.push_back(V.size() + 1);
// Push back a reference to last element when growing from large storage.
V.emplace_back(V.back());
EXPECT_EQ(int(V.size()) - 1, V.back());
}
template <class VectorT>
class SmallVectorInternalReferenceInvalidationTest
: public SmallVectorTestBase {
protected:
const char *AssertionMessage =
"Attempting to reference an element of the vector in an operation \" "
"\"that invalidates it";
VectorT V;
template <typename T, unsigned N>
static unsigned NumBuiltinElts(const SmallVector<T, N> &) {
return N;
}
void SetUp() override {
SmallVectorTestBase::SetUp();
// Fill up the small size so that insertions move the elements.
for (int I = 0, E = NumBuiltinElts(V); I != E; ++I)
V.emplace_back(I + 1, I + 1);
}
};
// Test pairs of the same types from SmallVectorReferenceInvalidationTestTypes.
using SmallVectorInternalReferenceInvalidationTestTypes =
::testing::Types<SmallVector<std::pair<int, int>, 3>,
SmallVector<std::pair<Constructable, Constructable>, 3>>;
TYPED_TEST_CASE(SmallVectorInternalReferenceInvalidationTest,
SmallVectorInternalReferenceInvalidationTestTypes);
TYPED_TEST(SmallVectorInternalReferenceInvalidationTest, EmplaceBack) {
// Note: setup adds [1, 2, ...] to V until it's at capacity in small mode.
auto &V = this->V;
int N = this->NumBuiltinElts(V);
// Push back a reference to last element when growing from small storage.
V.emplace_back(V.back().first, V.back().second);
EXPECT_EQ(N, V.back().first);
EXPECT_EQ(N, V.back().second);
// Check that the old value is still there (not moved away).
EXPECT_EQ(N, V[V.size() - 2].first);
EXPECT_EQ(N, V[V.size() - 2].second);
// Fill storage again.
V.back().first = V.back().second = V.size();
while (V.size() < V.capacity())
V.emplace_back(V.size() + 1, V.size() + 1);
// Push back a reference to last element when growing from large storage.
V.emplace_back(V.back().first, V.back().second);
EXPECT_EQ(int(V.size()) - 1, V.back().first);
EXPECT_EQ(int(V.size()) - 1, V.back().second);
}
} // end namespace