cpp-useful-iterators/test/capture_iterator_test.cxx

//
//  capture_iterator_test.cxx
//  iterator-test
//
//  Created by Sam Jaffe on 4/1/23.
//  Copyright © 2023 Sam Jaffe. All rights reserved.
//

#include "iterator/capture_iterator.h"

#include "ranges.h"
#include "xcode_gtest_helper.h"

using iterator::capture_iterator;

using testing::Address;
using testing::ElementsAre;
using testing::Not;

struct fake_iterator {
  using value_type = std::vector<int>;
  using reference = std::vector<int>;
  using pointer = void;
  using difference_type = std::ptrdiff_t;
  using iterator_category = std::output_iterator_tag;

  std::vector<int> operator*() const { return {0, 1, 2}; }
  void operator++() {}
  friend bool operator==(fake_iterator, fake_iterator) { return true; }
};

TEST(CaptureIterator, UnderlyingReturnsUnique) {
  auto it = fake_iterator();
  auto const & result = *it;
  EXPECT_THAT(*it, Not(Address(&result)));
}

TEST(CaptureIterator, CachesValue) {
  auto it = capture_iterator(fake_iterator());

  auto const & result = *it;
  EXPECT_THAT(*it, Address(&result));
}