Port Authentication Tracker - initial cut.

- With unit tests for behavior.

Change-Id: Icdf0c62268171e8c40d395366547a0bcaf612b61
diff --git a/apps/segmentrouting/src/test/java/org/onosproject/segmentrouting/AugmentedPortAuthTracker.java b/apps/segmentrouting/src/test/java/org/onosproject/segmentrouting/AugmentedPortAuthTracker.java
new file mode 100644
index 0000000..cc214e3
--- /dev/null
+++ b/apps/segmentrouting/src/test/java/org/onosproject/segmentrouting/AugmentedPortAuthTracker.java
@@ -0,0 +1,53 @@
+/*
+ * Copyright 2017-present Open Networking Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.onosproject.segmentrouting;
+
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.PortNumber;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * An augmented implementation of {@link PortAuthTracker}, so that we can
+ * instrument its behavior for unit test assertions.
+ */
+class AugmentedPortAuthTracker extends PortAuthTracker {
+
+    // instrument blocking flow activity, so we can see when we get hits
+    final List<ConnectPoint> installed = new ArrayList<>();
+    final List<ConnectPoint> cleared = new ArrayList<>();
+
+
+    void resetMetrics() {
+        installed.clear();
+        cleared.clear();
+    }
+
+    @Override
+    void installBlockingFlow(DeviceId d, PortNumber p) {
+        super.installBlockingFlow(d, p);
+        installed.add(new ConnectPoint(d, p));
+    }
+
+    @Override
+    void clearBlockingFlow(DeviceId d, PortNumber p) {
+        super.clearBlockingFlow(d, p);
+        cleared.add(new ConnectPoint(d, p));
+    }
+}