test/std/strings/string.view/string.view.template/starts_with.char.pass.cpp

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// UNSUPPORTED: c++03, c++11, c++14, c++17

// <string_view>

//   constexpr bool starts_with(charT x) const noexcept;

#include <string_view>
#include <cassert>

#include "test_macros.h"
#include "constexpr_char_traits.h"

int main(int, char**) {
  {
    typedef std::string_view SV;
    SV sv1{};
    SV sv2{"abcde", 5};

    ASSERT_NOEXCEPT(sv1.starts_with('e'));

    assert(!sv1.starts_with('a'));
    assert(!sv1.starts_with('x'));
    assert(sv2.starts_with('a'));
    assert(!sv2.starts_with('x'));
  }

#if TEST_STD_VER > 11
  {
    typedef std::basic_string_view<char, constexpr_char_traits<char>> SV;
    constexpr SV sv1{};
    constexpr SV sv2{"abcde", 5};
    static_assert(!sv1.starts_with('a'), "");
    static_assert(!sv1.starts_with('x'), "");
    static_assert(sv2.starts_with('a'), "");
    static_assert(!sv2.starts_with('x'), "");
  }
#endif

  return 0;
}