Make `HasAbslStringify` public.

PiperOrigin-RevId: 565050503
Change-Id: I8f4c463be4ef513a2788745d1b454a7ede489152

1 files changed, 37 insertions, 0 deletions

diff --git a/absl/strings/has_absl_stringify_test.cc b/absl/strings/has_absl_stringify_test.cc
new file mode 100644
index 00000000..e9915c66
--- /dev/null
+++ b/absl/strings/has_absl_stringify_test.cc
@@ -0,0 +1,37 @@
+// Copyright 2023 The Abseil Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "absl/strings/has_absl_stringify.h"
+
+#include <string>
+
+#include "gtest/gtest.h"
+
+namespace {
+
+struct TypeWithoutAbslStringify {};
+
+struct TypeWithAbslStringify {
+  template <typename Sink>
+  friend void AbslStringify(Sink&, const TypeWithAbslStringify&) {}
+};
+
+TEST(HasAbslStringifyTest, Works) {
+  EXPECT_FALSE(absl::HasAbslStringify<int>::value);
+  EXPECT_FALSE(absl::HasAbslStringify<std::string>::value);
+  EXPECT_FALSE(absl::HasAbslStringify<TypeWithoutAbslStringify>::value);
+  EXPECT_TRUE(absl::HasAbslStringify<TypeWithAbslStringify>::value);
+}
+
+}  // namespace