//===----------------------------------------------------------------------===//
//
// 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 size_type find(const charT* s, size_type pos, size_type n) const;

#include <string_view>
#include <cassert>

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

template <class S>
void
test(const S& s, const typename S::value_type* str, typename S::size_type pos,
     typename S::size_type n, typename S::size_type x)
{
    LIBCPP_ASSERT_NOEXCEPT(s.find(str, pos, n));
    assert(s.find(str, pos, n) == x);
    if (x != S::npos)
        assert(pos <= x && x + n <= s.size());
}

template <class S>
void test0()
{
    test(S(""), "", 0, 0, 0);
    test(S(""), "abcde", 0, 0, 0);
    test(S(""), "abcde", 0, 1, S::npos);
    test(S(""), "abcde", 0, 2, S::npos);
    test(S(""), "abcde", 0, 4, S::npos);
    test(S(""), "abcde", 0, 5, S::npos);
    test(S(""), "abcdeabcde", 0, 0, 0);
    test(S(""), "abcdeabcde", 0, 1, S::npos);
    test(S(""), "abcdeabcde", 0, 5, S::npos);
    test(S(""), "abcdeabcde", 0, 9, S::npos);
    test(S(""), "abcdeabcde", 0, 10, S::npos);
    test(S(""), "abcdeabcdeabcdeabcde", 0, 0, 0);
    test(S(""), "abcdeabcdeabcdeabcde", 0, 1, S::npos);
    test(S(""), "abcdeabcdeabcdeabcde", 0, 10, S::npos);
    test(S(""), "abcdeabcdeabcdeabcde", 0, 19, S::npos);
    test(S(""), "abcdeabcdeabcdeabcde", 0, 20, S::npos);
    test(S(""), "", 1, 0, S::npos);
    test(S(""), "abcde", 1, 0, S::npos);
    test(S(""), "abcde", 1, 1, S::npos);
    test(S(""), "abcde", 1, 2, S::npos);
    test(S(""), "abcde", 1, 4, S::npos);
    test(S(""), "abcde", 1, 5, S::npos);
    test(S(""), "abcdeabcde", 1, 0, S::npos);
    test(S(""), "abcdeabcde", 1, 1, S::npos);
    test(S(""), "abcdeabcde", 1, 5, S::npos);
    test(S(""), "abcdeabcde", 1, 9, S::npos);
    test(S(""), "abcdeabcde", 1, 10, S::npos);
    test(S(""), "abcdeabcdeabcdeabcde", 1, 0, S::npos);
    test(S(""), "abcdeabcdeabcdeabcde", 1, 1, S::npos);
    test(S(""), "abcdeabcdeabcdeabcde", 1, 10, S::npos);
    test(S(""), "abcdeabcdeabcdeabcde", 1, 19, S::npos);
    test(S(""), "abcdeabcdeabcdeabcde", 1, 20, S::npos);
    test(S("abcde"), "", 0, 0, 0);
    test(S("abcde"), "abcde", 0, 0, 0);
    test(S("abcde"), "abcde", 0, 1, 0);
    test(S("abcde"), "abcde", 0, 2, 0);
    test(S("abcde"), "abcde", 0, 4, 0);
    test(S("abcde"), "abcde", 0, 5, 0);
    test(S("abcde"), "abcdeabcde", 0, 0, 0);
    test(S("abcde"), "abcdeabcde", 0, 1, 0);
    test(S("abcde"), "abcdeabcde", 0, 5, 0);
    test(S("abcde"), "abcdeabcde", 0, 9, S::npos);
    test(S("abcde"), "abcdeabcde", 0, 10, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 0, 0, 0);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 0, 1, 0);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 0, 10, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 0, 19, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 0, 20, S::npos);
    test(S("abcde"), "", 1, 0, 1);
    test(S("abcde"), "abcde", 1, 0, 1);
    test(S("abcde"), "abcde", 1, 1, S::npos);
    test(S("abcde"), "abcde", 1, 2, S::npos);
    test(S("abcde"), "abcde", 1, 4, S::npos);
    test(S("abcde"), "abcde", 1, 5, S::npos);
    test(S("abcde"), "abcdeabcde", 1, 0, 1);
    test(S("abcde"), "abcdeabcde", 1, 1, S::npos);
    test(S("abcde"), "abcdeabcde", 1, 5, S::npos);
    test(S("abcde"), "abcdeabcde", 1, 9, S::npos);
    test(S("abcde"), "abcdeabcde", 1, 10, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 1, 0, 1);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 1, 1, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 1, 10, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 1, 19, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 1, 20, S::npos);
    test(S("abcde"), "", 2, 0, 2);
    test(S("abcde"), "abcde", 2, 0, 2);
    test(S("abcde"), "abcde", 2, 1, S::npos);
    test(S("abcde"), "abcde", 2, 2, S::npos);
    test(S("abcde"), "abcde", 2, 4, S::npos);
    test(S("abcde"), "abcde", 2, 5, S::npos);
    test(S("abcde"), "abcdeabcde", 2, 0, 2);
    test(S("abcde"), "abcdeabcde", 2, 1, S::npos);
    test(S("abcde"), "abcdeabcde", 2, 5, S::npos);
    test(S("abcde"), "abcdeabcde", 2, 9, S::npos);
    test(S("abcde"), "abcdeabcde", 2, 10, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 2, 0, 2);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 2, 1, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 2, 10, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 2, 19, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 2, 20, S::npos);
    test(S("abcde"), "", 4, 0, 4);
    test(S("abcde"), "abcde", 4, 0, 4);
    test(S("abcde"), "abcde", 4, 1, S::npos);
    test(S("abcde"), "abcde", 4, 2, S::npos);
    test(S("abcde"), "abcde", 4, 4, S::npos);
    test(S("abcde"), "abcde", 4, 5, S::npos);
    test(S("abcde"), "abcdeabcde", 4, 0, 4);
    test(S("abcde"), "abcdeabcde", 4, 1, S::npos);
    test(S("abcde"), "abcdeabcde", 4, 5, S::npos);
    test(S("abcde"), "abcdeabcde", 4, 9, S::npos);
    test(S("abcde"), "abcdeabcde", 4, 10, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 4, 0, 4);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 4, 1, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 4, 10, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 4, 19, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 4, 20, S::npos);
    test(S("abcde"), "", 5, 0, 5);
    test(S("abcde"), "abcde", 5, 0, 5);
    test(S("abcde"), "abcde", 5, 1, S::npos);
    test(S("abcde"), "abcde", 5, 2, S::npos);
}

template <class S>
void test1()
{
    test(S("abcde"), "abcde", 5, 4, S::npos);
    test(S("abcde"), "abcde", 5, 5, S::npos);
    test(S("abcde"), "abcdeabcde", 5, 0, 5);
    test(S("abcde"), "abcdeabcde", 5, 1, S::npos);
    test(S("abcde"), "abcdeabcde", 5, 5, S::npos);
    test(S("abcde"), "abcdeabcde", 5, 9, S::npos);
    test(S("abcde"), "abcdeabcde", 5, 10, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 5, 0, 5);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 5, 1, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 5, 10, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 5, 19, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 5, 20, S::npos);
    test(S("abcde"), "", 6, 0, S::npos);
    test(S("abcde"), "abcde", 6, 0, S::npos);
    test(S("abcde"), "abcde", 6, 1, S::npos);
    test(S("abcde"), "abcde", 6, 2, S::npos);
    test(S("abcde"), "abcde", 6, 4, S::npos);
    test(S("abcde"), "abcde", 6, 5, S::npos);
    test(S("abcde"), "abcdeabcde", 6, 0, S::npos);
    test(S("abcde"), "abcdeabcde", 6, 1, S::npos);
    test(S("abcde"), "abcdeabcde", 6, 5, S::npos);
    test(S("abcde"), "abcdeabcde", 6, 9, S::npos);
    test(S("abcde"), "abcdeabcde", 6, 10, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 6, 0, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 6, 1, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 6, 10, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 6, 19, S::npos);
    test(S("abcde"), "abcdeabcdeabcdeabcde", 6, 20, S::npos);
    test(S("abcdeabcde"), "", 0, 0, 0);
    test(S("abcdeabcde"), "abcde", 0, 0, 0);
    test(S("abcdeabcde"), "abcde", 0, 1, 0);
    test(S("abcdeabcde"), "abcde", 0, 2, 0);
    test(S("abcdeabcde"), "abcde", 0, 4, 0);
    test(S("abcdeabcde"), "abcde", 0, 5, 0);
    test(S("abcdeabcde"), "abcdeabcde", 0, 0, 0);
    test(S("abcdeabcde"), "abcdeabcde", 0, 1, 0);
    test(S("abcdeabcde"), "abcdeabcde", 0, 5, 0);
    test(S("abcdeabcde"), "abcdeabcde", 0, 9, 0);
    test(S("abcdeabcde"), "abcdeabcde", 0, 10, 0);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 0, 0, 0);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 0, 1, 0);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 0, 10, 0);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 0, 19, S::npos);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 0, 20, S::npos);
    test(S("abcdeabcde"), "", 1, 0, 1);
    test(S("abcdeabcde"), "abcde", 1, 0, 1);
    test(S("abcdeabcde"), "abcde", 1, 1, 5);
    test(S("abcdeabcde"), "abcde", 1, 2, 5);
    test(S("abcdeabcde"), "abcde", 1, 4, 5);
    test(S("abcdeabcde"), "abcde", 1, 5, 5);
    test(S("abcdeabcde"), "abcdeabcde", 1, 0, 1);
    test(S("abcdeabcde"), "abcdeabcde", 1, 1, 5);
    test(S("abcdeabcde"), "abcdeabcde", 1, 5, 5);
    test(S("abcdeabcde"), "abcdeabcde", 1, 9, S::npos);
    test(S("abcdeabcde"), "abcdeabcde", 1, 10, S::npos);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 1, 0, 1);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 1, 1, 5);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 1, 10, S::npos);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 1, 19, S::npos);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 1, 20, S::npos);
    test(S("abcdeabcde"), "", 5, 0, 5);
    test(S("abcdeabcde"), "abcde", 5, 0, 5);
    test(S("abcdeabcde"), "abcde", 5, 1, 5);
    test(S("abcdeabcde"), "abcde", 5, 2, 5);
    test(S("abcdeabcde"), "abcde", 5, 4, 5);
    test(S("abcdeabcde"), "abcde", 5, 5, 5);
    test(S("abcdeabcde"), "abcdeabcde", 5, 0, 5);
    test(S("abcdeabcde"), "abcdeabcde", 5, 1, 5);
    test(S("abcdeabcde"), "abcdeabcde", 5, 5, 5);
    test(S("abcdeabcde"), "abcdeabcde", 5, 9, S::npos);
    test(S("abcdeabcde"), "abcdeabcde", 5, 10, S::npos);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 5, 0, 5);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 5, 1, 5);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 5, 10, S::npos);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 5, 19, S::npos);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 5, 20, S::npos);
    test(S("abcdeabcde"), "", 9, 0, 9);
    test(S("abcdeabcde"), "abcde", 9, 0, 9);
    test(S("abcdeabcde"), "abcde", 9, 1, S::npos);
    test(S("abcdeabcde"), "abcde", 9, 2, S::npos);
    test(S("abcdeabcde"), "abcde", 9, 4, S::npos);
    test(S("abcdeabcde"), "abcde", 9, 5, S::npos);
    test(S("abcdeabcde"), "abcdeabcde", 9, 0, 9);
    test(S("abcdeabcde"), "abcdeabcde", 9, 1, S::npos);
    test(S("abcdeabcde"), "abcdeabcde", 9, 5, S::npos);
    test(S("abcdeabcde"), "abcdeabcde", 9, 9, S::npos);
    test(S("abcdeabcde"), "abcdeabcde", 9, 10, S::npos);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 9, 0, 9);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 9, 1, S::npos);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 9, 10, S::npos);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 9, 19, S::npos);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 9, 20, S::npos);
    test(S("abcdeabcde"), "", 10, 0, 10);
    test(S("abcdeabcde"), "abcde", 10, 0, 10);
    test(S("abcdeabcde"), "abcde", 10, 1, S::npos);
    test(S("abcdeabcde"), "abcde", 10, 2, S::npos);
    test(S("abcdeabcde"), "abcde", 10, 4, S::npos);
    test(S("abcdeabcde"), "abcde", 10, 5, S::npos);
    test(S("abcdeabcde"), "abcdeabcde", 10, 0, 10);
    test(S("abcdeabcde"), "abcdeabcde", 10, 1, S::npos);
}

template <class S>
void test2()
{
    test(S("abcdeabcde"), "abcdeabcde", 10, 5, S::npos);
    test(S("abcdeabcde"), "abcdeabcde", 10, 9, S::npos);
    test(S("abcdeabcde"), "abcdeabcde", 10, 10, S::npos);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 10, 0, 10);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 10, 1, S::npos);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 10, 10, S::npos);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 10, 19, S::npos);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 10, 20, S::npos);
    test(S("abcdeabcde"), "", 11, 0, S::npos);
    test(S("abcdeabcde"), "abcde", 11, 0, S::npos);
    test(S("abcdeabcde"), "abcde", 11, 1, S::npos);
    test(S("abcdeabcde"), "abcde", 11, 2, S::npos);
    test(S("abcdeabcde"), "abcde", 11, 4, S::npos);
    test(S("abcdeabcde"), "abcde", 11, 5, S::npos);
    test(S("abcdeabcde"), "abcdeabcde", 11, 0, S::npos);
    test(S("abcdeabcde"), "abcdeabcde", 11, 1, S::npos);
    test(S("abcdeabcde"), "abcdeabcde", 11, 5, S::npos);
    test(S("abcdeabcde"), "abcdeabcde", 11, 9, S::npos);
    test(S("abcdeabcde"), "abcdeabcde", 11, 10, S::npos);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 11, 0, S::npos);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 11, 1, S::npos);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 11, 10, S::npos);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 11, 19, S::npos);
    test(S("abcdeabcde"), "abcdeabcdeabcdeabcde", 11, 20, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "", 0, 0, 0);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 0, 0, 0);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 0, 1, 0);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 0, 2, 0);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 0, 4, 0);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 0, 5, 0);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 0, 0, 0);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 0, 1, 0);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 0, 5, 0);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 0, 9, 0);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 0, 10, 0);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 0, 0, 0);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 0, 1, 0);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 0, 10, 0);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 0, 19, 0);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 0, 20, 0);
    test(S("abcdeabcdeabcdeabcde"), "", 1, 0, 1);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 1, 0, 1);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 1, 1, 5);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 1, 2, 5);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 1, 4, 5);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 1, 5, 5);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 1, 0, 1);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 1, 1, 5);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 1, 5, 5);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 1, 9, 5);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 1, 10, 5);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 1, 0, 1);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 1, 1, 5);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 1, 10, 5);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 1, 19, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 1, 20, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "", 10, 0, 10);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 10, 0, 10);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 10, 1, 10);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 10, 2, 10);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 10, 4, 10);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 10, 5, 10);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 10, 0, 10);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 10, 1, 10);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 10, 5, 10);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 10, 9, 10);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 10, 10, 10);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 10, 0, 10);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 10, 1, 10);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 10, 10, 10);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 10, 19, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 10, 20, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "", 19, 0, 19);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 19, 0, 19);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 19, 1, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 19, 2, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 19, 4, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 19, 5, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 19, 0, 19);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 19, 1, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 19, 5, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 19, 9, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 19, 10, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 19, 0, 19);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 19, 1, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 19, 10, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 19, 19, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 19, 20, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "", 20, 0, 20);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 20, 0, 20);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 20, 1, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 20, 2, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 20, 4, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 20, 5, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 20, 0, 20);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 20, 1, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 20, 5, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 20, 9, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 20, 10, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 20, 0, 20);
}

template <class S>
void test3()
{
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 20, 1, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 20, 10, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 20, 19, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 20, 20, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "", 21, 0, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 21, 0, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 21, 1, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 21, 2, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 21, 4, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcde", 21, 5, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 21, 0, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 21, 1, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 21, 5, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 21, 9, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcde", 21, 10, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 21, 0, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 21, 1, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 21, 10, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 21, 19, S::npos);
    test(S("abcdeabcdeabcdeabcde"), "abcdeabcdeabcdeabcde", 21, 20, S::npos);
}

int main(int, char**)
{
    {
    typedef std::string_view S;
    test0<S>();
    test1<S>();
    test2<S>();
    test3<S>();
    }

#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.find( "",      0, 0 ) == 0, "" );
    static_assert (sv1.find( "abcde", 0, 0 ) == 0, "" );
    static_assert (sv1.find( "abcde", 0, 1 ) == SV::npos, "" );
    static_assert (sv2.find( "",      0, 0 ) == 0, "" );
    static_assert (sv2.find( "abcde", 0, 0 ) == 0, "" );
    static_assert (sv2.find( "abcde", 0, 1 ) == 0, "" );
    }
#endif

  return 0;
}
