cpp-useful-iterators/test/indexed_iterator_test.cxx

#include "iterator/indexed_iterator.hpp"

#include <vector>

#include <gmock/gmock.h>

using idx_iterator = iterator::indexed_iterator<std::vector<int>::iterator>;

// TODO: This ought to be implemented as a compiles-test
TEST(IndexedIteratorTest, CanCastCompatibleIterators) {
  std::vector<int> v{1, 2, 3, 4, 5};
  idx_iterator eai(v.begin());
  ::iterator::indexed_iterator<std::vector<int>::const_iterator>{eai};
}

TEST(IndexedIteratorTest, CanLieAboutIndex) {
  std::vector<int> vec{5, 3, 2, 8, 9, 11, 2, 4};
  idx_iterator it(vec.begin(), 3);
  EXPECT_THAT(it->first, 3);
}

TEST(IndexedIteratorTest, FakeIndexDoesntEffectEqualityCheck) {
  std::vector<int> vec{5, 3, 2, 8, 9, 11, 2, 4};
  EXPECT_THAT(idx_iterator(vec.begin()), idx_iterator(vec.begin(), 3));
}

TEST(IndexedIteratorTest, TreatsVectorIteratorAsMapIdxToValue) {
  std::vector<int> vec{5, 3, 2, 8, 9, 11, 2, 4};
  std::vector<std::pair<int, int>> const expected{
      {0, 5}, {1, 3}, {2, 2}, {3, 8}, {4, 9}, {5, 11}, {6, 2}, {7, 4}};

  std::vector<std::pair<int, int>> const result(idx_iterator(vec.begin()),
                                                idx_iterator(vec.end()));
  EXPECT_THAT(result, expected);
}

TEST(IndexedIteratorTest, CanMutatePointedToData) {
  std::vector<int> vec{5, 3, 2, 8, 9, 11, 2, 4};
  idx_iterator(vec.begin() + 4, 4)->second = -1;
  EXPECT_THAT(vec[4], -1);
}