test/std/strings/basic.string/string.starts_with/starts_with.string_view.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>

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

#include <string>
#include <cassert>

#include "test_macros.h"

template <class CharT, template <class> class Alloc>
constexpr void test_string() {
  using S       = std::basic_string<CharT, std::char_traits<CharT>, Alloc<CharT> >;
  using SV      = std::basic_string_view<CharT, std::char_traits<CharT> >;
  const char* s = "abcde";

  S s0;
  S s1{s, 1};
  S s2{s, 2};
  //  S   s3  { s, 3 };
  //  S   s4  { s, 4 };
  //  S   s5  { s, 5 };
  S sNot{"def", 3};

  SV sv0;
  SV sv1{s, 1};
  SV sv2{s, 2};
  SV sv3{s, 3};
  SV sv4{s, 4};
  SV sv5{s, 5};
  SV svNot{"def", 3};

  ASSERT_NOEXCEPT(s0.starts_with(sv0));

  assert(s0.starts_with(sv0));
  assert(!s0.starts_with(sv1));

  assert(s1.starts_with(sv0));
  assert(s1.starts_with(sv1));
  assert(!s1.starts_with(sv2));
  assert(!s1.starts_with(sv3));
  assert(!s1.starts_with(sv4));
  assert(!s1.starts_with(sv5));
  assert(!s1.starts_with(svNot));

  assert(s2.starts_with(sv0));
  assert(s2.starts_with(sv1));
  assert(s2.starts_with(sv2));
  assert(!s2.starts_with(sv3));
  assert(!s2.starts_with(sv4));
  assert(!s2.starts_with(sv5));
  assert(!s2.starts_with(svNot));

  assert(sNot.starts_with(sv0));
  assert(!sNot.starts_with(sv1));
  assert(!sNot.starts_with(sv2));
  assert(!sNot.starts_with(sv3));
  assert(!sNot.starts_with(sv4));
  assert(!sNot.starts_with(sv5));
  assert(sNot.starts_with(svNot));
}

constexpr bool test() {
  test_string<char, std::allocator>();

  return true;
}

int main(int, char**) {
  test();
  static_assert(test());

  return 0;
}