Exercise: Bag Of Items, By Unique Reference

Continuing from Exercise: Bag Of Items, By Copy, create a similar class BagUnique that contains pointers of type std::unique_ptr<Item> such that the tests below pass.

Special features:

• Find out: what would the return type of find_by_int() const be?

  • Can it be the vector’s member type, a std::unique_ptr<Item>? Why not?

  • A const std::unique_ptr<Item>& maybe? Why not?

• Try to create a std::unique_ptr<Item> and assign it to variable which you then insert, like (naively)

  auto v = std::make_unique<BagUnique::Item>("something", 42);
  bag.insert(v);
  

  Does it work? What do you notice?

code/bag-unique-suite.cpp

#include "bag-unique.h"

#include <gtest/gtest.h>

TEST(bag_unique_suite, find_by_int_ok)
{
    BagUnique bag;
    bag.insert(std::make_unique<BagUnique::Item>("something", 42));

    auto item2 = std::make_unique<BagUnique::Item>("anything", 666);
    bag.insert(std::move(item2));

    const BagUnique& constbag = bag;

    auto item = constbag.find_by_int(42);
    ASSERT_NE(item, nullptr);
    ASSERT_EQ(item->first, "something");
    ASSERT_EQ(item->second, 42);
}

TEST(bag_unique_suite, find_by_int_nok)
{
    BagUnique bag;
    bag.insert(std::make_unique<BagUnique::Item>("something", 42));
    bag.insert(std::make_unique<BagUnique::Item>("anything", 666));

    auto item = bag.find_by_int(7);
    ASSERT_EQ(item, nullptr);
}

TEST(bag_unique_suite, remove_by_int_ok)
{
    BagUnique bag;
    bag.insert(std::make_unique<BagUnique::Item>("something", 42));
    bag.insert(std::make_unique<BagUnique::Item>("anything", 666));

    std::size_t nremoved = bag.remove_by_int(42);
    ASSERT_EQ(nremoved, 1);
}