cpp-lazy-stream/test/common_test.cxx

//
//  common_test.cxx
//  stream-test
//
//  Created by Sam Jaffe on 4/2/23.
//

#include "stream/view/common.h"

#include "stream_helpers.h"
#include "stream_matchers.h"

using testing::StaticAssertTypeEq;

TEST(CommonView, CoercesSentinelIntoCommon) {
  Range<std::vector<int>, Sentinel> input;

  auto range = input | views::common();

  StaticAssertTypeEq<decltype(range.begin()), decltype(range.end())>();
}

TEST(CommonView, DoesNotWrapNonSentinelTypes) {
  Range<std::vector<int>, Common> input{0, 1, 2, 3, 4};

  auto range = input | views::common();

  StaticAssertTypeEq<decltype(input), decltype(range)>();
}

TEST(CommonView, IteratesThroughSameValues) {
  Range<std::vector<int>, Sentinel> input{0, 1, 2, 3, 4};

  auto range = input | views::common();

  EXPECT_THAT(range, RangesEq(input));
}

TEST(CommonView, NotRequiredToProvideSizeOrEmpty) {
  Range<std::vector<int>, Sentinel> input{0, 1, 2, 3, 4};

  auto range = input | views::common();

  static_assert(stream::detail::has_size_v<decltype(range)>);
  static_assert(stream::detail::has_empty_v<decltype(range)>);
}

TEST(CommonView, PropagatesSize) {
  Range<std::vector<int>, Sentinel, Sized> input{0, 1, 2, 3, 4};

  auto range = input | views::common();

  static_assert(stream::detail::has_size_v<decltype(range)>);
  EXPECT_THAT(range.size(), input.size());
}

TEST(CommonView, PropagatesEmpty) {
  Range<std::vector<int>, Sentinel, Sized> input{0, 1, 2, 3, 4};

  auto range = input | views::common();

  static_assert(stream::detail::has_empty_v<decltype(range)>);
  EXPECT_THAT(range.empty(), input.empty());
}