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> 20 TEST_CONSTEXPR_CXX20 void 21 test(const S& s) 22 { 23 ASSERT_NOEXCEPT(s.empty()); 24 assert(s.empty() == (s.size() == 0)); 25 } 26 27 template <class S> 28 TEST_CONSTEXPR_CXX20 void test_string() { 29 test(S()); 30 test(S("123")); 31 test(S("12345678901234567890123456789012345678901234567890")); 32 } 33 34 TEST_CONSTEXPR_CXX20 bool test() { 35 test_string<std::string>(); 36 #if TEST_STD_VER >= 11 37 test_string<std::basic_string<char, std::char_traits<char>, min_allocator<char>>>(); 38 #endif 39 40 return true; 41 } 42 43 int main(int, char**) 44 { 45 test(); 46 #if TEST_STD_VER > 17 47 static_assert(test()); 48 #endif 49 50 return 0; 51 } 52