libcxx/test/std/strings/string.view/string.view.cons/implicit_deduction_guides.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
  10 // UNSUPPORTED: libcpp-no-deduction-guides
  11
  12 // <string_view>
  13
  14 // Test that the constructors offered by std::basic_string_view are formulated
  15 // so they're compatible with implicit deduction guides.
  16
  17 #include <string_view>
  18 #include <cassert>
  19
  20 #include "test_macros.h"
  21 #include "constexpr_char_traits.h"
  22
  23 // Overloads
  24 // ---------------
  25 // (1)  basic_string_view() - NOT TESTED
  26 // (2)  basic_string_view(const basic_string_view&)
  27 // (3)  basic_string_view(const CharT*, size_type)
  28 // (4)  basic_string_view(const CharT*)
  29 int main(int, char**)
  30 {
  31   { // Testing (1)
  32     // Nothing to do. Cannot deduce without any arguments.
  33   }
  34   { // Testing (2)
  35     const std::string_view sin("abc");
  36     std::basic_string_view s(sin);
  37     ASSERT_SAME_TYPE(decltype(s), std::string_view);
  38     assert(s == "abc");
  39
  40     using WSV = std::basic_string_view<wchar_t, constexpr_char_traits<wchar_t>>;
  41     const WSV win(L"abcdef");
  42     std::basic_string_view w(win);
  43     ASSERT_SAME_TYPE(decltype(w), WSV);
  44     assert(w == L"abcdef");
  45   }
  46   { // Testing (3)
  47     std::basic_string_view s("abc", 2);
  48     ASSERT_SAME_TYPE(decltype(s), std::string_view);
  49     assert(s == "ab");
  50
  51     std::basic_string_view w(L"abcdef", 4);
  52     ASSERT_SAME_TYPE(decltype(w), std::wstring_view);
  53     assert(w == L"abcd");
  54   }
  55   { // Testing (4)
  56     std::basic_string_view s("abc");
  57     ASSERT_SAME_TYPE(decltype(s), std::string_view);
  58     assert(s == "abc");
  59
  60     std::basic_string_view w(L"abcdef");
  61     ASSERT_SAME_TYPE(decltype(w), std::wstring_view);
  62     assert(w == L"abcdef");
  63   }
  64
  65   return 0;
  66 }