add Rrset

Change-Id: Ic8a37ee63fb5b0266966d3888fba5d3d0a479b44
diff --git a/tests/unit/zone.cpp b/tests/unit/zone.cpp
index f533d2e..62dcb20 100644
--- a/tests/unit/zone.cpp
+++ b/tests/unit/zone.cpp
@@ -47,6 +47,16 @@
   BOOST_CHECK_NE(zone1, ndns::Zone("/net/ndnsim2"));
 }
 
+BOOST_AUTO_TEST_CASE(Ostream)
+{
+  ndns::Zone zone("/test");
+  zone.setId(1);
+
+  boost::test_tools::output_test_stream os;
+  os << zone;
+  BOOST_CHECK(os.is_equal("Zone: Id=1 Name=/test"));
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 } // namespace tests