[libc++] Prepare string.modifiers tests for constexpr

Reviewed By: ldionne, #libc

Spies: libcxx-commits

Differential Revision: https://reviews.llvm.org/D119329

1 files changed, 16 insertions, 7 deletions

diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/string_view.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/string_view.pass.cpp
index d0fb1cc3315e..7c0f6c2f027b 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_append/string_view.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_append/string_view.pass.cpp
@@ -19,7 +19,7 @@
 #include "min_allocator.h"
 
 template <class S, class SV>
-void
+TEST_CONSTEXPR_CXX20 void
 test(S s, SV sv, S expected)
 {
     s.append(sv);
@@ -27,9 +27,8 @@ test(S s, SV sv, S expected)
     assert(s == expected);
 }
 
-int main(int, char**)
-{
-    {
+bool test() {
+  {
     typedef std::string S;
     typedef std::string_view SV;
     test(S(), SV(), S());
@@ -52,9 +51,9 @@ int main(int, char**)
     test(S("12345678901234567890"), SV("1234567890"), S("123456789012345678901234567890"));
     test(S("12345678901234567890"), SV("12345678901234567890"),
          S("1234567890123456789012345678901234567890"));
-    }
+  }
 #if TEST_STD_VER >= 11
-    {
+  {
     typedef std::basic_string     <char, std::char_traits<char>, min_allocator<char>> S;
     typedef std::basic_string_view<char, std::char_traits<char> > SV;
     test(S(), SV(), S());
@@ -77,7 +76,17 @@ int main(int, char**)
     test(S("12345678901234567890"), SV("1234567890"), S("123456789012345678901234567890"));
     test(S("12345678901234567890"), SV("12345678901234567890"),
          S("1234567890123456789012345678901234567890"));
-    }
+  }
+#endif
+
+  return true;
+}
+
+int main(int, char**)
+{
+  test();
+#if TEST_STD_VER > 17
+  // static_assert(test());
 #endif
 
   return 0;