fix iterator test

Author: changkhothuychung

libcxx/test/std/ranges/range.adaptors/range.concat/iterator/compare.pass.cpp

@@ -29,6 +29,7 @@ constexpr void test() {
   };
 
   {
+    // test with one view
     std::array<int, 5> array{0, 1, 2, 3, 4};
     ConcatView view                          = make_concat_view(array.data(), array.data() + array.size());
     decltype(auto) it1                       = view.begin();
@@ -40,6 +41,22 @@ constexpr void test() {
     assert(!(it1 == it2));
   }
 
+  {
+    // test with more than one view
+    constexpr static std::array<int, 3> array1{0, 1, 2};
+    constexpr static std::array<int, 3> array2{0, 1, 2};
+    constexpr static std::ranges::concat_view view(std::views::all(array1), std::views::all(array2));
+    decltype(auto) it1                       = view.begin();
+    decltype(auto) it2                       = view.begin();
+    std::same_as<bool> decltype(auto) result = (it1 == it2);
+    assert(result);
+
+    ++it2; ++it2;
+    assert(!(it1 == it2));
+    ++it2;
+    assert(*it1 == *it2);
+  }
+
   {
     std::array<int, 5> array{0, 1, 2, 3, 4};
     ConcatView view = make_concat_view(array.data(), array.data() + array.size());

libcxx/test/std/ranges/range.adaptors/range.concat/iterator/decrement.pass.cpp

@@ -16,31 +16,33 @@
 #include "../types.h"
 
 constexpr void test() {
-  // Test with a single satisfied value
+  // Test with a single view
   {
     constexpr static std::array<int, 5> array{0, 1, 2, 3, 4};
     constexpr static std::ranges::concat_view view(std::views::all(array));
     auto it = std::ranges::next(view.begin(), view.end());
-    assert(it == view.end()); // test the test
+    assert(it == view.end());
 
     auto& result = --it;
     ASSERT_SAME_TYPE(decltype(result)&, decltype(--it));
     assert(&result == &it);
     assert(result == view.begin() + 4);
   }
 
-  // Test with more than one satisfied value
+  // Test with more than one view
   {
-    constexpr static std::array<int, 5> array{0, 1, 2, 3, 4};
-    constexpr static std::ranges::concat_view view(std::views::all(array));
+    constexpr static std::array<int, 3> array{0, 1, 2};
+    constexpr static std::array<int, 3> array1{3, 4, 5};
+    constexpr std::ranges::concat_view view(std::views::all(array), std::views::all(array1));
     auto it = std::ranges::next(view.begin(), view.end());
-    assert(it == view.end()); // test the test
+    assert(it == view.end());
 
     auto& result = --it;
     assert(&result == &it);
 
     --it;
-    assert(it == view.begin() + 3);
+    assert(*it == 4);
+    assert(it == view.begin() + 4);
   }
 
   // Test going forward and then backward on the same iterator

libcxx/test/std/ranges/range.adaptors/range.concat/iterator/deref.pass.cpp

@@ -17,21 +17,49 @@
 
 template <class Iter, class ValueType = int, class Sent = sentinel_wrapper<Iter>>
 constexpr void test() {
-  using View           = minimal_view<Iter, Sent>;
-  using ConcatView     = std::ranges::concat_view<View>;
-  using ConcatIterator = std::ranges::iterator_t<ConcatView>;
-
-  auto make_concat_view = [](auto begin, auto end) {
-    View view{Iter(begin), Sent(Iter(end))};
-    return ConcatView(std::move(view));
-  };
-
-  std::array array{0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
-  ConcatView view     = make_concat_view(array.data(), array.data() + array.size());
-  ConcatIterator iter = view.begin();
-  int& result         = *iter;
-  ASSERT_SAME_TYPE(int&, decltype(*iter));
-  assert(&result == array.data());
+
+  {
+    // test with one view
+    using View           = minimal_view<Iter, Sent>;
+    using ConcatView     = std::ranges::concat_view<View>;
+    using ConcatIterator = std::ranges::iterator_t<ConcatView>;
+
+    auto make_concat_view = [](auto begin, auto end) {
+      View view{Iter(begin), Sent(Iter(end))};
+      return ConcatView(std::move(view));
+    };
+
+    std::array array{0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
+    ConcatView view     = make_concat_view(array.data(), array.data() + array.size());
+    ConcatIterator iter = view.begin();
+    int& result         = *iter;
+    ASSERT_SAME_TYPE(int&, decltype(*iter));
+    assert(&result == array.data());
+  }
+
+  {
+    // test with more than one view
+    std::array<int, 3> array1{0, 1, 2};
+    std::array<int, 3> array2{0, 1, 2};
+    std::ranges::concat_view view(std::views::all(array1), std::views::all(array2));
+    decltype(auto) it1                       = view.begin();
+    decltype(auto) it2                       = view.begin() + 3;
+
+    ASSERT_SAME_TYPE(int&, decltype(*it1));
+    assert(*it1 == *it2);
+  }
+
+  {
+    // constness
+    constexpr static std::array<int, 3> array1{0, 1, 2};
+    constexpr static std::array<int, 3> array2{0, 1, 2};
+    constexpr static std::ranges::concat_view view(std::views::all(array1), std::views::all(array2));
+    decltype(auto) it1                       = view.begin();
+    decltype(auto) it2                       = view.begin() + 3;
+
+    ASSERT_SAME_TYPE(const int&, decltype(*it1));
+    assert(*it1 == *it2);
+  }
 }
 
 constexpr bool tests() {