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
  11 // <string_view>
  12
  13 // Test that the constructors offered by std::basic_string_view are formulated
  14 // so they're compatible with implicit deduction guides.
  15
  16 #include <string_view>
  17 #include <cassert>
  18
  19 #include "test_macros.h"
  20 #include "constexpr_char_traits.h"
  21
  22 // Overloads
  23 // ---------------
  24 // (1)  basic_string_view() - NOT TESTED
  25 // (2)  basic_string_view(const basic_string_view&)
  26 // (3)  basic_string_view(const CharT*, size_type)
  27 // (4)  basic_string_view(const CharT*)
  28 int main(int, char**) {
  29   {
  30     // Testing (1)
  31     // Nothing to do. Cannot deduce without any arguments.
  32   }
  33   { // Testing (2)
  34     const std::string_view sin("abc");
  35     std::basic_string_view s(sin);
  36     ASSERT_SAME_TYPE(decltype(s), std::string_view);
  37     assert(s == "abc");
  38
  39 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
  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 #endif
  46   }
  47   { // Testing (3)
  48     std::basic_string_view s("abc", 2);
  49     ASSERT_SAME_TYPE(decltype(s), std::string_view);
  50     assert(s == "ab");
  51
  52 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
  53     std::basic_string_view w(L"abcdef", 4);
  54     ASSERT_SAME_TYPE(decltype(w), std::wstring_view);
  55     assert(w == L"abcd");
  56 #endif
  57   }
  58   { // Testing (4)
  59     std::basic_string_view s("abc");
  60     ASSERT_SAME_TYPE(decltype(s), std::string_view);
  61     assert(s == "abc");
  62
  63 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
  64     std::basic_string_view w(L"abcdef");
  65     ASSERT_SAME_TYPE(decltype(w), std::wstring_view);
  66     assert(w == L"abcdef");
  67 #endif
  68   }
  69
  70   return 0;
  71 }