//===----------------------------------------------------------------------===//
//
// 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: !stdlib=libc++ && (c++03 || c++11 || c++14)

// <string_view>

// constexpr int compare(size_type pos1, size_type n1, const charT* s) const;

#include <string_view>
#include <cassert>
#include <stdexcept>

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

int sign(int x) { return x > 0 ? 1 : (x < 0 ? -1 : 0); }

template <typename CharT>
void test1(std::basic_string_view<CharT> sv1, std::size_t pos1, size_t n1, const CharT* s, int expected) {
#ifdef TEST_HAS_NO_EXCEPTIONS
  if (pos1 <= sv1.size())
    assert(sign(sv1.compare(pos1, n1, s)) == sign(expected));
#else
  try {
    assert(sign(sv1.compare(pos1, n1, s)) == sign(expected));
    assert(pos1 <= sv1.size());
  } catch (const std::out_of_range&) {
    assert(pos1 > sv1.size());
  }
#endif
}

template <typename CharT>
void test(const CharT* s1, std::size_t pos1, size_t n1, const CharT* s2, int expected) {
  typedef std::basic_string_view<CharT> string_view_t;
  string_view_t sv1(s1);
  test1(sv1, pos1, n1, s2, expected);
}

void test0() {
  test("", 0, 0, "", 0);
  test("", 0, 0, "abcde", -5);
  test("", 0, 0, "abcdefghij", -10);
  test("", 0, 0, "abcdefghijklmnopqrst", -20);
  test("", 0, 1, "", 0);
  test("", 0, 1, "abcde", -5);
  test("", 0, 1, "abcdefghij", -10);
  test("", 0, 1, "abcdefghijklmnopqrst", -20);
  test("", 1, 0, "", 0);
  test("", 1, 0, "abcde", 0);
  test("", 1, 0, "abcdefghij", 0);
  test("", 1, 0, "abcdefghijklmnopqrst", 0);
  test("abcde", 0, 0, "", 0);
  test("abcde", 0, 0, "abcde", -5);
  test("abcde", 0, 0, "abcdefghij", -10);
  test("abcde", 0, 0, "abcdefghijklmnopqrst", -20);
  test("abcde", 0, 1, "", 1);
  test("abcde", 0, 1, "abcde", -4);
  test("abcde", 0, 1, "abcdefghij", -9);
  test("abcde", 0, 1, "abcdefghijklmnopqrst", -19);
  test("abcde", 0, 2, "", 2);
  test("abcde", 0, 2, "abcde", -3);
  test("abcde", 0, 2, "abcdefghij", -8);
  test("abcde", 0, 2, "abcdefghijklmnopqrst", -18);
  test("abcde", 0, 4, "", 4);
  test("abcde", 0, 4, "abcde", -1);
  test("abcde", 0, 4, "abcdefghij", -6);
  test("abcde", 0, 4, "abcdefghijklmnopqrst", -16);
  test("abcde", 0, 5, "", 5);
  test("abcde", 0, 5, "abcde", 0);
  test("abcde", 0, 5, "abcdefghij", -5);
  test("abcde", 0, 5, "abcdefghijklmnopqrst", -15);
  test("abcde", 0, 6, "", 5);
  test("abcde", 0, 6, "abcde", 0);
  test("abcde", 0, 6, "abcdefghij", -5);
  test("abcde", 0, 6, "abcdefghijklmnopqrst", -15);
  test("abcde", 1, 0, "", 0);
  test("abcde", 1, 0, "abcde", -5);
  test("abcde", 1, 0, "abcdefghij", -10);
  test("abcde", 1, 0, "abcdefghijklmnopqrst", -20);
  test("abcde", 1, 1, "", 1);
  test("abcde", 1, 1, "abcde", 1);
  test("abcde", 1, 1, "abcdefghij", 1);
  test("abcde", 1, 1, "abcdefghijklmnopqrst", 1);
  test("abcde", 1, 2, "", 2);
  test("abcde", 1, 2, "abcde", 1);
  test("abcde", 1, 2, "abcdefghij", 1);
  test("abcde", 1, 2, "abcdefghijklmnopqrst", 1);
  test("abcde", 1, 3, "", 3);
  test("abcde", 1, 3, "abcde", 1);
  test("abcde", 1, 3, "abcdefghij", 1);
  test("abcde", 1, 3, "abcdefghijklmnopqrst", 1);
  test("abcde", 1, 4, "", 4);
  test("abcde", 1, 4, "abcde", 1);
  test("abcde", 1, 4, "abcdefghij", 1);
  test("abcde", 1, 4, "abcdefghijklmnopqrst", 1);
  test("abcde", 1, 5, "", 4);
  test("abcde", 1, 5, "abcde", 1);
  test("abcde", 1, 5, "abcdefghij", 1);
  test("abcde", 1, 5, "abcdefghijklmnopqrst", 1);
  test("abcde", 2, 0, "", 0);
  test("abcde", 2, 0, "abcde", -5);
  test("abcde", 2, 0, "abcdefghij", -10);
  test("abcde", 2, 0, "abcdefghijklmnopqrst", -20);
  test("abcde", 2, 1, "", 1);
  test("abcde", 2, 1, "abcde", 2);
  test("abcde", 2, 1, "abcdefghij", 2);
  test("abcde", 2, 1, "abcdefghijklmnopqrst", 2);
  test("abcde", 2, 2, "", 2);
  test("abcde", 2, 2, "abcde", 2);
  test("abcde", 2, 2, "abcdefghij", 2);
  test("abcde", 2, 2, "abcdefghijklmnopqrst", 2);
  test("abcde", 2, 3, "", 3);
  test("abcde", 2, 3, "abcde", 2);
  test("abcde", 2, 3, "abcdefghij", 2);
  test("abcde", 2, 3, "abcdefghijklmnopqrst", 2);
  test("abcde", 2, 4, "", 3);
  test("abcde", 2, 4, "abcde", 2);
  test("abcde", 2, 4, "abcdefghij", 2);
  test("abcde", 2, 4, "abcdefghijklmnopqrst", 2);
  test("abcde", 4, 0, "", 0);
  test("abcde", 4, 0, "abcde", -5);
  test("abcde", 4, 0, "abcdefghij", -10);
  test("abcde", 4, 0, "abcdefghijklmnopqrst", -20);
  test("abcde", 4, 1, "", 1);
  test("abcde", 4, 1, "abcde", 4);
  test("abcde", 4, 1, "abcdefghij", 4);
  test("abcde", 4, 1, "abcdefghijklmnopqrst", 4);
  test("abcde", 4, 2, "", 1);
  test("abcde", 4, 2, "abcde", 4);
  test("abcde", 4, 2, "abcdefghij", 4);
  test("abcde", 4, 2, "abcdefghijklmnopqrst", 4);
  test("abcde", 5, 0, "", 0);
  test("abcde", 5, 0, "abcde", -5);
  test("abcde", 5, 0, "abcdefghij", -10);
  test("abcde", 5, 0, "abcdefghijklmnopqrst", -20);
  test("abcde", 5, 1, "", 0);
  test("abcde", 5, 1, "abcde", -5);
  test("abcde", 5, 1, "abcdefghij", -10);
  test("abcde", 5, 1, "abcdefghijklmnopqrst", -20);
}

void test1() {
  test("abcde", 6, 0, "", 0);
  test("abcde", 6, 0, "abcde", 0);
  test("abcde", 6, 0, "abcdefghij", 0);
  test("abcde", 6, 0, "abcdefghijklmnopqrst", 0);
  test("abcdefghij", 0, 0, "", 0);
  test("abcdefghij", 0, 0, "abcde", -5);
  test("abcdefghij", 0, 0, "abcdefghij", -10);
  test("abcdefghij", 0, 0, "abcdefghijklmnopqrst", -20);
  test("abcdefghij", 0, 1, "", 1);
  test("abcdefghij", 0, 1, "abcde", -4);
  test("abcdefghij", 0, 1, "abcdefghij", -9);
  test("abcdefghij", 0, 1, "abcdefghijklmnopqrst", -19);
  test("abcdefghij", 0, 5, "", 5);
  test("abcdefghij", 0, 5, "abcde", 0);
  test("abcdefghij", 0, 5, "abcdefghij", -5);
  test("abcdefghij", 0, 5, "abcdefghijklmnopqrst", -15);
  test("abcdefghij", 0, 9, "", 9);
  test("abcdefghij", 0, 9, "abcde", 4);
  test("abcdefghij", 0, 9, "abcdefghij", -1);
  test("abcdefghij", 0, 9, "abcdefghijklmnopqrst", -11);
  test("abcdefghij", 0, 10, "", 10);
  test("abcdefghij", 0, 10, "abcde", 5);
  test("abcdefghij", 0, 10, "abcdefghij", 0);
  test("abcdefghij", 0, 10, "abcdefghijklmnopqrst", -10);
  test("abcdefghij", 0, 11, "", 10);
  test("abcdefghij", 0, 11, "abcde", 5);
  test("abcdefghij", 0, 11, "abcdefghij", 0);
  test("abcdefghij", 0, 11, "abcdefghijklmnopqrst", -10);
  test("abcdefghij", 1, 0, "", 0);
  test("abcdefghij", 1, 0, "abcde", -5);
  test("abcdefghij", 1, 0, "abcdefghij", -10);
  test("abcdefghij", 1, 0, "abcdefghijklmnopqrst", -20);
  test("abcdefghij", 1, 1, "", 1);
  test("abcdefghij", 1, 1, "abcde", 1);
  test("abcdefghij", 1, 1, "abcdefghij", 1);
  test("abcdefghij", 1, 1, "abcdefghijklmnopqrst", 1);
  test("abcdefghij", 1, 4, "", 4);
  test("abcdefghij", 1, 4, "abcde", 1);
  test("abcdefghij", 1, 4, "abcdefghij", 1);
  test("abcdefghij", 1, 4, "abcdefghijklmnopqrst", 1);
  test("abcdefghij", 1, 8, "", 8);
  test("abcdefghij", 1, 8, "abcde", 1);
  test("abcdefghij", 1, 8, "abcdefghij", 1);
  test("abcdefghij", 1, 8, "abcdefghijklmnopqrst", 1);
  test("abcdefghij", 1, 9, "", 9);
  test("abcdefghij", 1, 9, "abcde", 1);
  test("abcdefghij", 1, 9, "abcdefghij", 1);
  test("abcdefghij", 1, 9, "abcdefghijklmnopqrst", 1);
  test("abcdefghij", 1, 10, "", 9);
  test("abcdefghij", 1, 10, "abcde", 1);
  test("abcdefghij", 1, 10, "abcdefghij", 1);
  test("abcdefghij", 1, 10, "abcdefghijklmnopqrst", 1);
  test("abcdefghij", 5, 0, "", 0);
  test("abcdefghij", 5, 0, "abcde", -5);
  test("abcdefghij", 5, 0, "abcdefghij", -10);
  test("abcdefghij", 5, 0, "abcdefghijklmnopqrst", -20);
  test("abcdefghij", 5, 1, "", 1);
  test("abcdefghij", 5, 1, "abcde", 5);
  test("abcdefghij", 5, 1, "abcdefghij", 5);
  test("abcdefghij", 5, 1, "abcdefghijklmnopqrst", 5);
  test("abcdefghij", 5, 2, "", 2);
  test("abcdefghij", 5, 2, "abcde", 5);
  test("abcdefghij", 5, 2, "abcdefghij", 5);
  test("abcdefghij", 5, 2, "abcdefghijklmnopqrst", 5);
  test("abcdefghij", 5, 4, "", 4);
  test("abcdefghij", 5, 4, "abcde", 5);
  test("abcdefghij", 5, 4, "abcdefghij", 5);
  test("abcdefghij", 5, 4, "abcdefghijklmnopqrst", 5);
  test("abcdefghij", 5, 5, "", 5);
  test("abcdefghij", 5, 5, "abcde", 5);
  test("abcdefghij", 5, 5, "abcdefghij", 5);
  test("abcdefghij", 5, 5, "abcdefghijklmnopqrst", 5);
  test("abcdefghij", 5, 6, "", 5);
  test("abcdefghij", 5, 6, "abcde", 5);
  test("abcdefghij", 5, 6, "abcdefghij", 5);
  test("abcdefghij", 5, 6, "abcdefghijklmnopqrst", 5);
  test("abcdefghij", 9, 0, "", 0);
  test("abcdefghij", 9, 0, "abcde", -5);
  test("abcdefghij", 9, 0, "abcdefghij", -10);
  test("abcdefghij", 9, 0, "abcdefghijklmnopqrst", -20);
  test("abcdefghij", 9, 1, "", 1);
  test("abcdefghij", 9, 1, "abcde", 9);
  test("abcdefghij", 9, 1, "abcdefghij", 9);
  test("abcdefghij", 9, 1, "abcdefghijklmnopqrst", 9);
  test("abcdefghij", 9, 2, "", 1);
  test("abcdefghij", 9, 2, "abcde", 9);
  test("abcdefghij", 9, 2, "abcdefghij", 9);
  test("abcdefghij", 9, 2, "abcdefghijklmnopqrst", 9);
  test("abcdefghij", 10, 0, "", 0);
  test("abcdefghij", 10, 0, "abcde", -5);
  test("abcdefghij", 10, 0, "abcdefghij", -10);
  test("abcdefghij", 10, 0, "abcdefghijklmnopqrst", -20);
  test("abcdefghij", 10, 1, "", 0);
  test("abcdefghij", 10, 1, "abcde", -5);
  test("abcdefghij", 10, 1, "abcdefghij", -10);
  test("abcdefghij", 10, 1, "abcdefghijklmnopqrst", -20);
  test("abcdefghij", 11, 0, "", 0);
  test("abcdefghij", 11, 0, "abcde", 0);
  test("abcdefghij", 11, 0, "abcdefghij", 0);
  test("abcdefghij", 11, 0, "abcdefghijklmnopqrst", 0);
}

void test2() {
  test("abcdefghijklmnopqrst", 0, 0, "", 0);
  test("abcdefghijklmnopqrst", 0, 0, "abcde", -5);
  test("abcdefghijklmnopqrst", 0, 0, "abcdefghij", -10);
  test("abcdefghijklmnopqrst", 0, 0, "abcdefghijklmnopqrst", -20);
  test("abcdefghijklmnopqrst", 0, 1, "", 1);
  test("abcdefghijklmnopqrst", 0, 1, "abcde", -4);
  test("abcdefghijklmnopqrst", 0, 1, "abcdefghij", -9);
  test("abcdefghijklmnopqrst", 0, 1, "abcdefghijklmnopqrst", -19);
  test("abcdefghijklmnopqrst", 0, 10, "", 10);
  test("abcdefghijklmnopqrst", 0, 10, "abcde", 5);
  test("abcdefghijklmnopqrst", 0, 10, "abcdefghij", 0);
  test("abcdefghijklmnopqrst", 0, 10, "abcdefghijklmnopqrst", -10);
  test("abcdefghijklmnopqrst", 0, 19, "", 19);
  test("abcdefghijklmnopqrst", 0, 19, "abcde", 14);
  test("abcdefghijklmnopqrst", 0, 19, "abcdefghij", 9);
  test("abcdefghijklmnopqrst", 0, 19, "abcdefghijklmnopqrst", -1);
  test("abcdefghijklmnopqrst", 0, 20, "", 20);
  test("abcdefghijklmnopqrst", 0, 20, "abcde", 15);
  test("abcdefghijklmnopqrst", 0, 20, "abcdefghij", 10);
  test("abcdefghijklmnopqrst", 0, 20, "abcdefghijklmnopqrst", 0);
  test("abcdefghijklmnopqrst", 0, 21, "", 20);
  test("abcdefghijklmnopqrst", 0, 21, "abcde", 15);
  test("abcdefghijklmnopqrst", 0, 21, "abcdefghij", 10);
  test("abcdefghijklmnopqrst", 0, 21, "abcdefghijklmnopqrst", 0);
  test("abcdefghijklmnopqrst", 1, 0, "", 0);
  test("abcdefghijklmnopqrst", 1, 0, "abcde", -5);
  test("abcdefghijklmnopqrst", 1, 0, "abcdefghij", -10);
  test("abcdefghijklmnopqrst", 1, 0, "abcdefghijklmnopqrst", -20);
  test("abcdefghijklmnopqrst", 1, 1, "", 1);
  test("abcdefghijklmnopqrst", 1, 1, "abcde", 1);
  test("abcdefghijklmnopqrst", 1, 1, "abcdefghij", 1);
  test("abcdefghijklmnopqrst", 1, 1, "abcdefghijklmnopqrst", 1);
  test("abcdefghijklmnopqrst", 1, 9, "", 9);
  test("abcdefghijklmnopqrst", 1, 9, "abcde", 1);
  test("abcdefghijklmnopqrst", 1, 9, "abcdefghij", 1);
  test("abcdefghijklmnopqrst", 1, 9, "abcdefghijklmnopqrst", 1);
  test("abcdefghijklmnopqrst", 1, 18, "", 18);
  test("abcdefghijklmnopqrst", 1, 18, "abcde", 1);
  test("abcdefghijklmnopqrst", 1, 18, "abcdefghij", 1);
  test("abcdefghijklmnopqrst", 1, 18, "abcdefghijklmnopqrst", 1);
  test("abcdefghijklmnopqrst", 1, 19, "", 19);
  test("abcdefghijklmnopqrst", 1, 19, "abcde", 1);
  test("abcdefghijklmnopqrst", 1, 19, "abcdefghij", 1);
  test("abcdefghijklmnopqrst", 1, 19, "abcdefghijklmnopqrst", 1);
  test("abcdefghijklmnopqrst", 1, 20, "", 19);
  test("abcdefghijklmnopqrst", 1, 20, "abcde", 1);
  test("abcdefghijklmnopqrst", 1, 20, "abcdefghij", 1);
  test("abcdefghijklmnopqrst", 1, 20, "abcdefghijklmnopqrst", 1);
  test("abcdefghijklmnopqrst", 10, 0, "", 0);
  test("abcdefghijklmnopqrst", 10, 0, "abcde", -5);
  test("abcdefghijklmnopqrst", 10, 0, "abcdefghij", -10);
  test("abcdefghijklmnopqrst", 10, 0, "abcdefghijklmnopqrst", -20);
  test("abcdefghijklmnopqrst", 10, 1, "", 1);
  test("abcdefghijklmnopqrst", 10, 1, "abcde", 10);
  test("abcdefghijklmnopqrst", 10, 1, "abcdefghij", 10);
  test("abcdefghijklmnopqrst", 10, 1, "abcdefghijklmnopqrst", 10);
  test("abcdefghijklmnopqrst", 10, 5, "", 5);
  test("abcdefghijklmnopqrst", 10, 5, "abcde", 10);
  test("abcdefghijklmnopqrst", 10, 5, "abcdefghij", 10);
  test("abcdefghijklmnopqrst", 10, 5, "abcdefghijklmnopqrst", 10);
  test("abcdefghijklmnopqrst", 10, 9, "", 9);
  test("abcdefghijklmnopqrst", 10, 9, "abcde", 10);
  test("abcdefghijklmnopqrst", 10, 9, "abcdefghij", 10);
  test("abcdefghijklmnopqrst", 10, 9, "abcdefghijklmnopqrst", 10);
  test("abcdefghijklmnopqrst", 10, 10, "", 10);
  test("abcdefghijklmnopqrst", 10, 10, "abcde", 10);
  test("abcdefghijklmnopqrst", 10, 10, "abcdefghij", 10);
  test("abcdefghijklmnopqrst", 10, 10, "abcdefghijklmnopqrst", 10);
  test("abcdefghijklmnopqrst", 10, 11, "", 10);
  test("abcdefghijklmnopqrst", 10, 11, "abcde", 10);
  test("abcdefghijklmnopqrst", 10, 11, "abcdefghij", 10);
  test("abcdefghijklmnopqrst", 10, 11, "abcdefghijklmnopqrst", 10);
  test("abcdefghijklmnopqrst", 19, 0, "", 0);
  test("abcdefghijklmnopqrst", 19, 0, "abcde", -5);
  test("abcdefghijklmnopqrst", 19, 0, "abcdefghij", -10);
  test("abcdefghijklmnopqrst", 19, 0, "abcdefghijklmnopqrst", -20);
  test("abcdefghijklmnopqrst", 19, 1, "", 1);
  test("abcdefghijklmnopqrst", 19, 1, "abcde", 19);
  test("abcdefghijklmnopqrst", 19, 1, "abcdefghij", 19);
  test("abcdefghijklmnopqrst", 19, 1, "abcdefghijklmnopqrst", 19);
  test("abcdefghijklmnopqrst", 19, 2, "", 1);
  test("abcdefghijklmnopqrst", 19, 2, "abcde", 19);
  test("abcdefghijklmnopqrst", 19, 2, "abcdefghij", 19);
  test("abcdefghijklmnopqrst", 19, 2, "abcdefghijklmnopqrst", 19);
  test("abcdefghijklmnopqrst", 20, 0, "", 0);
  test("abcdefghijklmnopqrst", 20, 0, "abcde", -5);
  test("abcdefghijklmnopqrst", 20, 0, "abcdefghij", -10);
  test("abcdefghijklmnopqrst", 20, 0, "abcdefghijklmnopqrst", -20);
  test("abcdefghijklmnopqrst", 20, 1, "", 0);
  test("abcdefghijklmnopqrst", 20, 1, "abcde", -5);
  test("abcdefghijklmnopqrst", 20, 1, "abcdefghij", -10);
  test("abcdefghijklmnopqrst", 20, 1, "abcdefghijklmnopqrst", -20);
  test("abcdefghijklmnopqrst", 21, 0, "", 0);
  test("abcdefghijklmnopqrst", 21, 0, "abcde", 0);
  test("abcdefghijklmnopqrst", 21, 0, "abcdefghij", 0);
  test("abcdefghijklmnopqrst", 21, 0, "abcdefghijklmnopqrst", 0);
}

int main(int, char**) {
  test0();
  test1();
  test2();

  {
    test("", 0, 0, "", 0);
    test("", 0, 0, "abcde", -5);
    test("", 0, 0, "abcdefghij", -10);
    test("", 0, 0, "abcdefghijklmnopqrst", -20);
    test("abcde", 0, 2, "", 5);
    test("abcde", 0, 6, "abcde", 0);
    test("abcde", 0, 6, "abcdefghij", -5);
    test("abcde", 0, 6, "abcdefghijklmnopqrst", -15);
    test("abcdefghij", 3, 3, "", 10);
    test("abcdefghij", 3, 3, "abcde", 5);
    test("abcdefghij", 3, 3, "def", 0);
    test("abcdefghij", 0, 4, "abcdefghijklmnopqrst", -10);
    test("abcdefghijklmnopqrst", 5, 5, "", 20);
    test("abcdefghijklmnopqrst", 0, 8, "abcde", 15);
    test("abcdefghijklmnopqrst", 0, 12, "abcdefghij", 10);
    test("abcdefghijklmnopqrst", 0, static_cast<std::size_t>(-1), "abcdefghijklmnopqrst", 0);
  }

#ifndef TEST_HAS_NO_WIDE_CHARACTERS
  {
    test(L"", 0, 0, L"", 0);
    test(L"", 0, 0, L"abcde", -5);
    test(L"", 0, 0, L"abcdefghij", -10);
    test(L"", 0, 0, L"abcdefghijklmnopqrst", -20);
    test(L"abcde", 0, 2, L"", 5);
    test(L"abcde", 0, 6, L"abcde", 0);
    test(L"abcde", 0, 6, L"abcdefghij", -5);
    test(L"abcde", 0, 6, L"abcdefghijklmnopqrst", -15);
    test(L"abcdefghij", 3, 3, L"", 10);
    test(L"abcdefghij", 3, 3, L"abcde", 5);
    test(L"abcdefghij", 3, 3, L"def", 0);
    test(L"abcdefghij", 0, 4, L"abcdefghijklmnopqrst", -10);
    test(L"abcdefghijklmnopqrst", 5, 5, L"", 20);
    test(L"abcdefghijklmnopqrst", 0, 8, L"abcde", 15);
    test(L"abcdefghijklmnopqrst", 0, 12, L"abcdefghij", 10);
    test(L"abcdefghijklmnopqrst", 0, static_cast<std::size_t>(-1), L"abcdefghijklmnopqrst", 0);
  }
#endif

#if TEST_STD_VER >= 11
  {
    test(U"", 0, 0, U"", 0);
    test(U"", 0, 0, U"abcde", -5);
    test(U"", 0, 0, U"abcdefghij", -10);
    test(U"", 0, 0, U"abcdefghijklmnopqrst", -20);
    test(U"abcde", 0, 2, U"", 5);
    test(U"abcde", 0, 6, U"abcde", 0);
    test(U"abcde", 0, 6, U"abcdefghij", -5);
    test(U"abcde", 0, 6, U"abcdefghijklmnopqrst", -15);
    test(U"abcdefghij", 3, 3, U"", 10);
    test(U"abcdefghij", 3, 3, U"abcde", 5);
    test(U"abcdefghij", 3, 3, U"def", 0);
    test(U"abcdefghij", 0, 4, U"abcdefghijklmnopqrst", -10);
    test(U"abcdefghijklmnopqrst", 5, 5, U"", 20);
    test(U"abcdefghijklmnopqrst", 0, 8, U"abcde", 15);
    test(U"abcdefghijklmnopqrst", 0, 12, U"abcdefghij", 10);
    test(U"abcdefghijklmnopqrst", 0, static_cast<std::size_t>(-1), U"abcdefghijklmnopqrst", 0);
  }

  {
    test(u"", 0, 0, u"", 0);
    test(u"", 0, 0, u"abcde", -5);
    test(u"", 0, 0, u"abcdefghij", -10);
    test(u"", 0, 0, u"abcdefghijklmnopqrst", -20);
    test(u"abcde", 0, 2, u"", 5);
    test(u"abcde", 0, 6, u"abcde", 0);
    test(u"abcde", 0, 6, u"abcdefghij", -5);
    test(u"abcde", 0, 6, u"abcdefghijklmnopqrst", -15);
    test(u"abcdefghij", 3, 3, u"", 10);
    test(u"abcdefghij", 3, 3, u"abcde", 5);
    test(u"abcdefghij", 3, 3, u"def", 0);
    test(u"abcdefghij", 0, 4, u"abcdefghijklmnopqrst", -10);
    test(u"abcdefghijklmnopqrst", 5, 5, u"", 20);
    test(u"abcdefghijklmnopqrst", 0, 8, u"abcde", 15);
    test(u"abcdefghijklmnopqrst", 0, 12, u"abcdefghij", 10);
    test(u"abcdefghijklmnopqrst", 0, static_cast<std::size_t>(-1), u"abcdefghijklmnopqrst", 0);
  }
#endif

#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.compare(0, 0, "") == 0, "");
    static_assert(sv1.compare(0, 0, "abcde") < 0, "");
    static_assert(sv2.compare(0, 2, "") > 0, "");
    static_assert(sv2.compare(0, 6, "abcde") == 0, "");
  }
#endif

  return 0;
}
