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>::const_iterator>;

TEST(IndexedIteratorTest, TreatsVectorIteratorAsMapIdxToValue) {
  std::vector<int> const vec{5, 3, 2, 8, 9, 11, 2, 4};
  idx_iterator it{vec.begin()}, end{vec.end()};
  for (; it != end; ++it) {
    EXPECT_THAT((*it).second, vec[(*it).first]);
  }
}

TEST(IndexedIteratorTest, ContainsReferencesToContainersElements) {
  std::vector<int> const vec{5, 3, 2, 8, 9, 11, 2, 4};
  idx_iterator it{vec.begin()}, end{vec.end()};
  for (; it != end; ++it) {
    EXPECT_THAT(&(*it).second, &vec[(*it).first]);
  }
}