xref: /llvm-project/libcxx/test/std/strings/basic.string/string.capacity/empty.pass.cpp (revision a40bada91aeda276a772acfbcae6e8de26755a11)
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 // <string>
10 
11 // bool empty() const noexcept; // constexpr since C++20
12 
13 #include <string>
14 #include <cassert>
15 
16 #include "test_macros.h"
17 #include "min_allocator.h"
18 
19 template <class S>
test(const S & s)20 TEST_CONSTEXPR_CXX20 void test(const S& s) {
21   ASSERT_NOEXCEPT(s.empty());
22   assert(s.empty() == (s.size() == 0));
23 }
24 
25 template <class S>
test_string()26 TEST_CONSTEXPR_CXX20 void test_string() {
27   test(S());
28   test(S("123"));
29   test(S("12345678901234567890123456789012345678901234567890"));
30 }
31 
test()32 TEST_CONSTEXPR_CXX20 bool test() {
33   test_string<std::string>();
34 #if TEST_STD_VER >= 11
35   test_string<std::basic_string<char, std::char_traits<char>, min_allocator<char>>>();
36 #endif
37 
38   return true;
39 }
40 
main(int,char **)41 int main(int, char**) {
42   test();
43 #if TEST_STD_VER > 17
44   static_assert(test());
45 #endif
46 
47   return 0;
48 }
49