Implement basic unit tests for RouteHandler

In addition,
    - Refactor Segment Routing unit test mocking

Change-Id: I94cb75a8b12944264faa76301d58ee19f246d584
diff --git a/src/test/java/org/onosproject/segmentrouting/MockRoutingRulePopulator.java b/src/test/java/org/onosproject/segmentrouting/MockRoutingRulePopulator.java
new file mode 100644
index 0000000..4eab7c0
--- /dev/null
+++ b/src/test/java/org/onosproject/segmentrouting/MockRoutingRulePopulator.java
@@ -0,0 +1,54 @@
+/*
+ * 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.onlab.packet.IpPrefix;
+import org.onlab.packet.MacAddress;
+import org.onlab.packet.VlanId;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.PortNumber;
+
+import java.util.Map;
+
+/**
+ * Mock Routing Rule Populator.
+ */
+public class MockRoutingRulePopulator extends RoutingRulePopulator {
+    private Map<MockRoutingTableKey, MockRoutingTableValue> routingTable;
+
+    MockRoutingRulePopulator(SegmentRoutingManager srManager,
+                             Map<MockRoutingTableKey, MockRoutingTableValue> routingTable) {
+        super(srManager);
+        this.routingTable = routingTable;
+    }
+
+    @Override
+    public void populateRoute(DeviceId deviceId, IpPrefix prefix,
+                              MacAddress hostMac, VlanId hostVlanId, PortNumber outPort) {
+        MockRoutingTableKey rtKey = new MockRoutingTableKey(deviceId, prefix);
+        MockRoutingTableValue rtValue = new MockRoutingTableValue(outPort, hostMac, hostVlanId);
+        routingTable.put(rtKey, rtValue);
+    }
+
+    @Override
+    public void revokeRoute(DeviceId deviceId, IpPrefix prefix,
+                            MacAddress hostMac, VlanId hostVlanId, PortNumber outPort) {
+        MockRoutingTableKey rtKey = new MockRoutingTableKey(deviceId, prefix);
+        MockRoutingTableValue rtValue = new MockRoutingTableValue(outPort, hostMac, hostVlanId);
+        routingTable.remove(rtKey, rtValue);
+    }
+}
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