libcxx/test/std/ranges/range.factories/range.single.view/cpo.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // UNSUPPORTED: c++03, c++11, c++14, c++17
  10
  11 // std::views::single
  12
  13 #include <ranges>
  14
  15 #include <cassert>
  16 #include <concepts>
  17 #include <utility>
  18 #include "MoveOnly.h"
  19
  20 // Can't invoke without arguments.
  21 static_assert(!std::is_invocable_v<decltype((std::views::single))>);
  22 #if _LIBCPP_STD_VER >= 23
  23 // Can invoke with a move-only type.
  24 static_assert(std::is_invocable_v<decltype((std::views::single)), MoveOnly>);
  25 #endif
  26 constexpr bool test() {
  27   // Lvalue.
  28   {
  29     int x = 42;
  30     std::same_as<std::ranges::single_view<int>> decltype(auto) v = std::views::single(x);
  31     assert(v.size() == 1);
  32     assert(v.front() == x);
  33   }
  34
  35   // Prvalue.
  36   {
  37     std::same_as<std::ranges::single_view<int>> decltype(auto) v = std::views::single(42);
  38     assert(v.size() == 1);
  39     assert(v.front() == 42);
  40   }
  41
  42   // Const lvalue.
  43   {
  44     const int x = 42;
  45     std::same_as<std::ranges::single_view<int>> decltype(auto) v = std::views::single(x);
  46     assert(v.size() == 1);
  47     assert(v.front() == x);
  48   }
  49
  50   // Xvalue.
  51   {
  52     int x = 42;
  53     std::same_as<std::ranges::single_view<int>> decltype(auto) v = std::views::single(std::move(x));
  54     assert(v.size() == 1);
  55     assert(v.front() == x);
  56   }
  57
  58   return true;
  59 }
  60
  61 int main(int, char**) {
  62   test();
  63   static_assert(test());
  64
  65   return 0;
  66 }