Unit test to Router class with Async ARP

Change-Id: I3797433ae5dcce06425159887e42ee75bcf621e4
diff --git a/apps/sdnip/src/test/java/org/onlab/onos/sdnip/RouterTest.java b/apps/sdnip/src/test/java/org/onlab/onos/sdnip/RouterTest.java
index 6d77a2c..13547ae 100644
--- a/apps/sdnip/src/test/java/org/onlab/onos/sdnip/RouterTest.java
+++ b/apps/sdnip/src/test/java/org/onlab/onos/sdnip/RouterTest.java
@@ -69,6 +69,8 @@
 /**
  * This class tests adding a route, updating a route, deleting a route,
  * and adding a route whose next hop is the local BGP speaker.
+ * <p/>
+ * ARP module answers the MAC address synchronously.
  */
 public class RouterTest {