1 files changed, 56 insertions, 0 deletions
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.pback/sungetc.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.pback/sungetc.pass.cpp
new file mode 100644
index 00000000000..4c68fada07a
--- /dev/null
+++ b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.pback/sungetc.pass.cpp
@@ -0,0 +1,56 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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.
+//
+//===----------------------------------------------------------------------===//
+
+// <streambuf>
+
+// template <class charT, class traits = char_traits<charT> >
+// class basic_streambuf;
+
+// int_type sungetc();
+
+#include <streambuf>
+#include <cassert>
+
+int pbackfail_called = 0;
+
+struct test
+    : public std::basic_streambuf<char>
+{
+    typedef std::basic_streambuf<char> base;
+
+    test() {}
+
+    void setg(char* gbeg, char* gnext, char* gend)
+    {
+        base::setg(gbeg, gnext, gend);
+    }
+
+protected:
+    int_type pbackfail(int_type c = traits_type::eof())
+    {
+        ++pbackfail_called;
+        return 'a';
+    }
+};
+
+int main()
+{
+    {
+        test t;
+        assert(pbackfail_called == 0);
+        assert(t.sungetc() == 'a');
+        assert(pbackfail_called == 1);
+        char in[] = "ABC";
+        t.setg(in, in+1, in+sizeof(in));
+        assert(t.sungetc() == 'A');
+        assert(pbackfail_called == 1);
+        assert(t.sungetc() == 'a');
+        assert(pbackfail_called == 2);
+    }
+}