Construct GraphDescription with online/active Device/Link only

Change-Id: I9312c0c8ae190bf0200bd040823b6f7a3e7a15e1
diff --git a/core/net/src/test/java/org/onlab/onos/net/topology/impl/DefaultTopologyProviderTest.java b/core/net/src/test/java/org/onlab/onos/net/topology/impl/DefaultTopologyProviderTest.java
index 56594233..7e67c6d 100644
--- a/core/net/src/test/java/org/onlab/onos/net/topology/impl/DefaultTopologyProviderTest.java
+++ b/core/net/src/test/java/org/onlab/onos/net/topology/impl/DefaultTopologyProviderTest.java
@@ -154,6 +154,11 @@
                                    device("e"), device("f"));
         }
 
+        @Override
+        public Iterable<Device> getAvailableDevices() {
+            return getDevices();
+        }
+
         void post(DeviceEvent event) {
             eventDispatcher.post(event);
         }
@@ -174,6 +179,11 @@
                                    link("e", 1, "f", 1), link("f", 1, "e", 1));
         }
 
+        @Override
+        public Iterable<Link> getActiveLinks() {
+            return getLinks();
+        }
+
         void post(LinkEvent event) {
             eventDispatcher.post(event);
         }