face: Allow creation of Face with custom IO service and default transport

Change-Id: I3f3a77c980d23f5ff53d21d4669582caff259a63
Refs: #2500
diff --git a/tests/unit-tests/face.t.cpp b/tests/unit-tests/face.t.cpp
index 928a050..5c8dda0 100644
--- a/tests/unit-tests/face.t.cpp
+++ b/tests/unit-tests/face.t.cpp
@@ -602,9 +602,9 @@
 
   BOOST_CHECK(Face().getTransport() != nullptr);
 
-  BOOST_CHECK(Face(shared_ptr<Transport>()).getTransport() == nullptr);
-  BOOST_CHECK(Face(shared_ptr<Transport>(), io).getTransport() == nullptr);
-  BOOST_CHECK(Face(shared_ptr<Transport>(), io, keyChain).getTransport() == nullptr);
+  BOOST_CHECK(Face(shared_ptr<Transport>()).getTransport() != nullptr);
+  BOOST_CHECK(Face(shared_ptr<Transport>(), io).getTransport() != nullptr);
+  BOOST_CHECK(Face(shared_ptr<Transport>(), io, keyChain).getTransport() != nullptr);
 
   auto transport = make_shared<TcpTransport>("localhost", "6363"); // no real io operations will be scheduled
   BOOST_CHECK(Face(transport).getTransport() == transport);