tests: Small correction to make test case more stable

Change-Id: I720499212a3857df2e1467cfee8c7e1f4decdf78
diff --git a/tests/unit-tests/dummy-client-face.hpp b/tests/unit-tests/dummy-client-face.hpp
index d8789bd..b744882 100644
--- a/tests/unit-tests/dummy-client-face.hpp
+++ b/tests/unit-tests/dummy-client-face.hpp
@@ -90,6 +90,14 @@
     m_transport->m_sentDatas     = &m_sentDatas;
   }
 
+  DummyClientFace(shared_ptr<DummyClientTransport> transport, boost::asio::io_service& ioService)
+    : Face(transport, ioService)
+    , m_transport(transport)
+  {
+    m_transport->m_sentInterests = &m_sentInterests;
+    m_transport->m_sentDatas     = &m_sentDatas;
+  }
+
   /** \brief cause the Face to receive a packet
    */
   template<typename Packet>
@@ -121,6 +129,12 @@
   return make_shared<DummyClientFace>(make_shared<DummyClientTransport>());
 }
 
+inline shared_ptr<DummyClientFace>
+makeDummyClientFace(boost::asio::io_service& ioService)
+{
+  return make_shared<DummyClientFace>(make_shared<DummyClientTransport>(), ref(ioService));
+}
+
 } // namespace tests
 } // namespace ndn