From 7aacdd05bd4d6fa1305d6671521dd01d28b622c3 Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Fri, 3 Jun 2022 02:10:06 -0600
Subject: [PATCH] [cplusplus] Test hashing shared_ptr / unique_ptr

---
 test/api/test-cplusplus.cc | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/test/api/test-cplusplus.cc b/test/api/test-cplusplus.cc
index d742750f6..28b5e21ab 100644
--- a/test/api/test-cplusplus.cc
+++ b/test/api/test-cplusplus.cc
@@ -62,6 +62,7 @@
 #include "hb-cplusplus.hh"
 
 #include <cassert>
+#include <functional>
 #include <utility>
 
 int
@@ -108,5 +109,16 @@ main ()
 
   hb::unique_ptr<hb_buffer_t> pb5 {pb3.reference ()};
 
+
+  /* Test that shared_ptr / unique_ptr are std::hash'able, and that they
+   * return the same hash (which is the underlying pointer's hash. */
+  std::hash<hb_buffer_t *> hash {};
+  std::hash<hb::shared_ptr<hb_buffer_t>> hash2 {};
+  std::hash<hb::unique_ptr<hb_buffer_t>> hash3 {};
+
+  assert (hash (b) == hash2 (pb4));
+  assert (hash2 (pb4) == hash2 (pb2));
+  assert (hash (b) == hash3 (pb5));
+
   return pb == pb.get_empty () || pb == pb2;
 }