sync with N3126

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@113101 91177308-0d34-0410-b5e6-96231b3b80d8

test/containers/container.adaptors/stack/stack.defn/top.pass.cpp

@@ -0,0 +1,26 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <stack>
+
+// reference top();
+
+#include <stack>
+#include <cassert>
+
+int main()
+{
+    std::stack<int> q;
+    assert(q.size() == 0);
+    q.push(1);
+    q.push(2);
+    q.push(3);
+    int& ir = q.top();
+    assert(ir == 3);
+}