link provider tests

Change-Id: I074d067a1432c874fa0e1674423df046d4c31086
diff --git a/providers/openflow/link/src/main/java/org/onlab/onos/provider/of/link/impl/LinkDiscovery.java b/providers/openflow/link/src/main/java/org/onlab/onos/provider/of/link/impl/LinkDiscovery.java
index 1c98ad9..132b185 100644
--- a/providers/openflow/link/src/main/java/org/onlab/onos/provider/of/link/impl/LinkDiscovery.java
+++ b/providers/openflow/link/src/main/java/org/onlab/onos/provider/of/link/impl/LinkDiscovery.java
@@ -86,7 +86,7 @@
     private final boolean useBDDP;
     private final OpenFlowController ctrl;
     private final LinkProviderService linkProvider;
-    private final Map<Integer, OFPortDesc> ports;
+    protected final Map<Integer, OFPortDesc> ports;
     private Timeout timeout;
 
     /**
diff --git a/providers/openflow/link/src/main/java/org/onlab/onos/provider/of/link/impl/OpenFlowLinkProvider.java b/providers/openflow/link/src/main/java/org/onlab/onos/provider/of/link/impl/OpenFlowLinkProvider.java
index f448a44..f1e3861 100644
--- a/providers/openflow/link/src/main/java/org/onlab/onos/provider/of/link/impl/OpenFlowLinkProvider.java
+++ b/providers/openflow/link/src/main/java/org/onlab/onos/provider/of/link/impl/OpenFlowLinkProvider.java
@@ -29,6 +29,7 @@
 import org.projectfloodlight.openflow.protocol.OFPortStatus;
 import org.slf4j.Logger;
 
+
 /**
  * Provider which uses an OpenFlow controller to detect network
  * infrastructure links.
@@ -50,7 +51,7 @@
 
     private final InternalLinkProvider listener = new InternalLinkProvider();
 
-    private final Map<Dpid, LinkDiscovery> discoverers = new ConcurrentHashMap<>();
+    protected final Map<Dpid, LinkDiscovery> discoverers = new ConcurrentHashMap<>();
 
     /**
      * Creates an OpenFlow link provider.
@@ -138,7 +139,7 @@
 
         @Override
         public void roleAssertFailed(Dpid dpid, RoleState role) {
-            // TODO Auto-generated method stub
+            // do nothing for this.
         }
 
     }