1 files changed, 71 insertions, 0 deletions
diff --git a/test/std/containers/unord/unord.set/extract_key.pass.cpp b/test/std/containers/unord/unord.set/extract_key.pass.cpp
new file mode 100644
index 000000000000..f686342b298e
--- /dev/null
+++ b/test/std/containers/unord/unord.set/extract_key.pass.cpp
@@ -0,0 +1,71 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// <unordered_set>
+
+// class unordered_set
+
+// node_type extract(key_type const&);
+
+#include <unordered_set>
+#include "min_allocator.h"
+#include "Counter.h"
+
+template <class Container, class KeyTypeIter>
+void test(Container& c, KeyTypeIter first, KeyTypeIter last)
+{
+    size_t sz = c.size();
+    assert((size_t)std::distance(first, last) == sz);
+
+    for (KeyTypeIter copy = first; copy != last; ++copy)
+    {
+        typename Container::node_type t = c.extract(*copy);
+        assert(!t.empty());
+        --sz;
+        assert(t.value() == *copy);
+        assert(t.get_allocator() == c.get_allocator());
+        assert(sz == c.size());
+    }
+
+    assert(c.size() == 0);
+
+    for (KeyTypeIter copy = first; copy != last; ++copy)
+    {
+        typename Container::node_type t = c.extract(*copy);
+        assert(t.empty());
+    }
+}
+
+int main()
+{
+    {
+        std::unordered_set<int> m = {1, 2, 3, 4, 5, 6};
+        int keys[] = {1, 2, 3, 4, 5, 6};
+        test(m, std::begin(keys), std::end(keys));
+    }
+
+    {
+        std::unordered_set<Counter<int>> m = {1, 2, 3, 4, 5, 6};
+        {
+            Counter<int> keys[] = {1, 2, 3, 4, 5, 6};
+            assert(Counter_base::gConstructed == 6+6);
+            test(m, std::begin(keys), std::end(keys));
+        }
+        assert(Counter_base::gConstructed == 0);
+    }
+
+    {
+        using min_alloc_set = std::unordered_set<int, std::hash<int>, std::equal_to<int>, min_allocator<int>>;
+        min_alloc_set m = {1, 2, 3, 4, 5, 6};
+        int keys[] = {1, 2, 3, 4, 5, 6};
+        test(m, std::begin(keys), std::end(keys));
+    }
+}