From 4499c613374b91ea3e5d7bd1165314b324afa06f Mon Sep 17 00:00:00 2001
From: Alex Guteniev <gutenev@gmail.com>
Date: Mon, 14 Aug 2023 19:25:16 +0300
Subject: [PATCH] Test

Also copied from @wangzw PR
---
 test/std-test.cc | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/test/std-test.cc b/test/std-test.cc
index d0617a73..80871940 100644
--- a/test/std-test.cc
+++ b/test/std-test.cc
@@ -244,3 +244,14 @@ TEST(std_test, format_atomic) {
   const std::atomic<bool> cb(true);
   EXPECT_EQ(fmt::format("{}", cb), "true");
 }
+
+#if defined(__cpp_lib_atomic_flag_test) && __cpp_lib_atomic_flag_test >= 201907L
+TEST(std_test, format_atomic_flag) {
+  std::atomic_flag f = ATOMIC_FLAG_INIT;
+  (void) f.test_and_set();
+  EXPECT_EQ(fmt::format("{}", f), "true");
+
+  const std::atomic<bool> cf = ATOMIC_FLAG_INIT;
+  EXPECT_EQ(fmt::format("{}", cf), "false");
+}
+#endif // defined(__cpp_lib_atomic_flag_test) && __cpp_lib_atomic_flag_test >= 201907L