tests: add support for link-local addresses in getTestIp

Change-Id: If57cb93f1c25a18b680aef12895ee5924ca90cfa
diff --git a/tests/daemon/face/unicast-udp-transport-fixture.hpp b/tests/daemon/face/unicast-udp-transport-fixture.hpp
index ef8f588..f3c5165 100644
--- a/tests/daemon/face/unicast-udp-transport-fixture.hpp
+++ b/tests/daemon/face/unicast-udp-transport-fixture.hpp
@@ -47,7 +47,7 @@
   UnicastUdpTransportFixture()
     : transport(nullptr)
     , remoteSocket(g_io)
-    , defaultAddr(getTestIp<AddressFamily::V4>())
+    , defaultAddr(getTestIp(AddressFamily::V4, AddressScope::Loopback))
     , receivedPackets(nullptr)
   {
   }