cpp-useful-iterators/test/end_aware_iterator_test.cxx

#include "iterator/end_aware_iterator.hpp"

#include <vector>

#include "xcode_gtest_helper.h"

using end_aware_iterator =
    ::iterator::end_aware_iterator<std::vector<int>::iterator>;

TEST(EndAwareIteratorTest, IsConstructedFromInputs) {
  std::vector<int> v{1, 2, 3, 4, 5};
  auto begin = v.begin(), end = v.end();
  end_aware_iterator eai(begin, end);
  EXPECT_THAT(eai.current(), begin);
  EXPECT_THAT(eai.end(), end);
}

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

TEST(EndAwareIteratorTest, BeginWrapperIsEqualToBegin) {
  std::vector<int> v{1, 2, 3, 4, 5};
  EXPECT_THAT(*v.begin(), *end_aware_iterator(v.begin(), v.end()));
}

TEST(EndAwareIteratorTest, MutableActionsArePassthrough) {
  std::vector<int> v{1, 2, 3, 4, 5};
  *end_aware_iterator(v.begin(), v.end()) = -1;
  EXPECT_THAT(v[0], -1);
}

TEST(EndAwareIteratorTest, CanTellYouThatItsReachedEnd) {
  std::vector<int> v{1, 2, 3, 4, 5};
  end_aware_iterator it{v.end() - 1, v.end()};
  EXPECT_FALSE(it.at_end());
  ++it;
  EXPECT_THAT(it, end_aware_iterator(v.end(), v.end()));
  EXPECT_TRUE(it.at_end());
}

TEST(EndAwareIteratorTest, SingleArgIsEnd) {
  std::vector<int> v{1, 2, 3, 4, 5};
  EXPECT_TRUE(end_aware_iterator(v.begin()).at_end());
}

TEST(EndAwareIteratorTest, EmptyIteratorIsEnd) {
  EXPECT_TRUE(end_aware_iterator().at_end());
}

TEST(EndAwareIteratorTest, AllEndPointsAreEqual) {
  std::vector<int> v1{1, 2, 3, 4, 5};
  std::vector<int> v2{8, 9, 10};
  EXPECT_THAT(end_aware_iterator(v1.end(), v1.end()),
              end_aware_iterator(v2.end(), v2.end()));
}

TEST(EndAwareIteratorTest, PreIncrementAdvancesIterator) {
  std::vector<int> v{1, 2, 3, 4, 5};
  end_aware_iterator eai(v.begin(), v.end());
  EXPECT_THAT(*eai, 1);
  EXPECT_THAT(*++eai, 2);
  EXPECT_THAT(*eai, 2);
}

TEST(EndAwareIteratorTest, PostIncrementReturnsCopyOfPrev) {
  std::vector<int> v{1, 2, 3, 4, 5};
  end_aware_iterator eai(v.begin(), v.end());
  EXPECT_THAT(*eai, 1);
  EXPECT_THAT(*eai++, 1);
  EXPECT_THAT(*eai, 2);
}

TEST(EndAwareIteratorTest, IncrementOnEndIsUnsafe) {
  std::vector<int> v{1, 2, 3, 4, 5};
  end_aware_iterator it{v.end(), v.end()};
  end_aware_iterator const cp = it;
  ++it;
  EXPECT_NE(it, cp);
}