add test

Author: changkhothuychung

libcxx/test/std/ranges/range.adaptors/range.concat/ctor.verify.cpp

@@ -15,9 +15,8 @@
 
 #include "test_macros.h"
 
-struct NoSizeRange : std::ranges::view_base {
-  constexpr auto size() { return 0; }
-};
+template <typename... Ts>
+concept ViewWithAtLeastOneElement = requires(Ts...&& a) { std::views::concat(a...); };
 
 int main(int, char**) {
   {
@@ -36,9 +35,13 @@ int main(int, char**) {
   }
 
   {
-    // input is a view but has 0 size
-    auto c = std::views::concat(NoSizeRange{});
-    // expected-error@*:* {{}}
+    // input is a view and has 0 size
+    static_assert(!ViewWithAtLeastOneElement<>);
+  }
+
+  {
+    // input is a view and has at least an element
+    static_assert(ViewWithAtLeastOneElement<std::vector<int>>);
   }
 
   {

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

@@ -8,6 +8,22 @@
 
 // REQUIRES: std-at-least-c++26
 
+// friend constexpr iterator operator-(const iterator& it, difference_type n)
+//         requires concat-is-random-access<Const, Views...>;
+
+// friend constexpr difference_type operator-(const iterator& x, const iterator& y)
+//     requires concat-is-random-access<Const, Views...>;
+
+// friend constexpr difference_type operator-(default_sentinel_t, const __iterator& __x)
+//     requires(sized_sentinel_for<sentinel_t<__maybe_const<_Const, _Views>>, iterator_t<__maybe_const<_Const, _Views>>> &&
+//              ...) &&
+//             (__all_but_first_model_sized_range<_Const, _Views...>::value)
+
+// friend constexpr difference_type operator-(const __iterator& __x, default_sentinel_t)
+//     requires(sized_sentinel_for<sentinel_t<__maybe_const<_Const, _Views>>, iterator_t<__maybe_const<_Const, _Views>>> &&
+//              ...) &&
+//             (__all_but_first_model_sized_range<_Const, _Views...>::value)
+
 #include <array>
 #include <concepts>
 #include <functional>
@@ -78,6 +94,26 @@ constexpr bool test() {
     assert((it1 - it2) == -11);
   }
 
+  {
+    // operator-(sentinel, x)
+    std::array<int, 2> array1{0, 1};
+    std::array<int, 2> array2{2, 3};
+    std::ranges::concat_view view(std::views::all(array1), std::views::all(array2));
+    auto it1 = view.begin();
+    auto res = std::default_sentinel_t{} - it1;
+    assert(res == 4);
+  }
+
+  {
+    // operator-(x, sentinel)
+    std::array<int, 2> array1{0, 1};
+    std::array<int, 2> array2{2, 3};
+    std::ranges::concat_view view(std::views::all(array1), std::views::all(array2));
+    auto it1 = view.begin();
+    auto res = it1 - std::default_sentinel_t{};
+    assert(res == -4);
+  }
+
   {
     // One of the ranges is not random access
     std::ranges::concat_view v(a, b, ForwardSizedView{buffer1});

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

@@ -57,6 +57,23 @@ constexpr void test() {
     assert(*it1 == *it2);
   }
 
+  {
+    // test with more than one view and iterators are in different range
+    constexpr static std::array<int, 3> array1{0, 1, 2};
+    constexpr static std::array<int, 3> array2{4, 5, 6};
+    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(it1 != it2);
+    assert(*it1 = 0);
+    assert(*it1 = 4);
+    it1++;
+    it2++;
+    assert(*it1 = 1);
+    assert(*it1 = 5);
+  }
+
   {
     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/deref.pass.cpp

@@ -50,6 +50,29 @@ constexpr void test() {
     assert(*it1 == *it2);
   }
 
+  {
+    // test with more than one view of different types
+    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<int, 3> array1{0, 1, 2};
+    std::array<int, 3> array2{3, 4, 5};
+    ConcatView view = make_concat_view(array1.data(), array1.data() + array1.size());
+    std::ranges::concat_view cv(view, std::views::all(array2));
+    decltype(auto) it1 = cv.begin();
+    decltype(auto) it2 = cv.begin() + 3;
+
+    ASSERT_SAME_TYPE(int&, decltype(*it1));
+    assert(*it1 == 0);
+    assert(*it2 == 3);
+  }
+
   {
     // constness
     constexpr static std::array<int, 3> array1{0, 1, 2};