diff --git a/src/test/java/net/onrc/onos/intent/ConstrainedShortestPathIntentTest.java b/src/test/java/net/onrc/onos/intent/ConstrainedShortestPathIntentTest.java
index 354e053..e8759b1 100644
--- a/src/test/java/net/onrc/onos/intent/ConstrainedShortestPathIntentTest.java
+++ b/src/test/java/net/onrc/onos/intent/ConstrainedShortestPathIntentTest.java
@@ -11,6 +11,9 @@
 import com.esotericsoftware.kryo.io.Input;
 import com.esotericsoftware.kryo.io.Output;
 
+/**
+ * @author Toshio Koide (t-koide@onlab.us)
+ */
 public class ConstrainedShortestPathIntentTest {
 	NetworkGraph g;
 
diff --git a/src/test/java/net/onrc/onos/intent/IntentMapTest.java b/src/test/java/net/onrc/onos/intent/IntentMapTest.java
index bad546d..b636167 100644
--- a/src/test/java/net/onrc/onos/intent/IntentMapTest.java
+++ b/src/test/java/net/onrc/onos/intent/IntentMapTest.java
@@ -1,12 +1,21 @@
 package net.onrc.onos.intent;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
+import net.onrc.onos.intent.ErrorIntent.ErrorType;
 import net.onrc.onos.intent.Intent.IntentState;
+import net.onrc.onos.intent.IntentMap.ChangedEventType;
+import net.onrc.onos.intent.IntentOperation.Operator;
+import net.onrc.onos.intent.runtime.IntentStateList;
 
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 
+/**
+ * @author Toshio Koide (t-koide@onlab.us)
+ */
 public class IntentMapTest {
 
 	@Before
@@ -18,55 +27,212 @@
 	}
 
 	@Test
-	public void test() {
+	public void testCreate() {
 		IntentMap intents = new IntentMap();
-		IntentOperationList operations = new IntentOperationList();
+		assertEquals(0, intents.getAllIntents().size());
+	}
 
-		// add three intents
+	@Test
+	public void testChangedEventCreate() {
+		IntentMap intents = new IntentMap();
+		IntentMap.ChangedEvent event = intents.new ChangedEvent(
+				ChangedEventType.ADDED,
+				new Intent("id1"));
+		assertEquals(ChangedEventType.ADDED, event.eventType);
+		assertEquals("id1", event.intent.getId());
+	}
 
-		ShortestPathIntent intent1 =
-				new ShortestPathIntent("1", 11L, 12L, 13L, 14L, 15L, 16L);
+	@Test
+	public void testAddOperations() {
+		IntentMap intents = new IntentMap();
+		assertEquals(0, intents.getAllIntents().size());
+
+		Intent intent1 = new Intent("1");
 		ShortestPathIntent intent2 =
 				new ShortestPathIntent("2", 21L, 22L, 23L, 24L, 25L, 26L);
 		ConstrainedShortestPathIntent intent3 =
 				new ConstrainedShortestPathIntent("3", 31L, 32L, 33L, 34L, 35L, 36L, 1000.0);
 
-		operations.add(new IntentOperation(IntentOperation.Operator.ADD, intent1));
-		operations.add(new IntentOperation(IntentOperation.Operator.ADD, intent2));
-		operations.add(new IntentOperation(IntentOperation.Operator.ADD, intent3));
+		IntentOperationList operations = new IntentOperationList();
+		operations.add(Operator.ADD, intent1);
+		operations.add(Operator.ADD, intent2);
+		operations.add(Operator.ADD, intent3);
+		assertEquals(3, operations.size());
+
 		intents.executeOperations(operations);
-
-		// check
-
 		assertEquals(3, intents.getAllIntents().size());
-		assertEquals(intent1, intents.getIntent("1"));
-		assertEquals(intent2, intents.getIntent("2"));
-		assertEquals(intent3, intents.getIntent("3"));
+		assertSame(intent1, intents.getIntent("1"));
+		assertSame(intent2, intents.getIntent("2"));
+		assertSame(intent3, intents.getIntent("3"));
+	}
 
-		// request removal of an intent
+	@Test
+	public void testAddOperationsOverwrite() {
+		IntentMap intents = new IntentMap();
 
+		Intent intent1 = new Intent("1");
+		Intent intent2 = new Intent("2");
+		Intent intent3 = new Intent("3");
 		Intent intent4 = new Intent("1");
+		Intent intent5 = new Intent("2");
+		Intent intent6 = new Intent("4");
+
+		IntentOperationList operations = new IntentOperationList();
+		operations.add(Operator.ADD, intent1);
+		operations.add(Operator.ADD, intent2);
+		operations.add(Operator.ADD, intent3);
+		assertEquals(3, operations.size());
+
+		intents.executeOperations(operations);
+		assertEquals(3, intents.getAllIntents().size());
+		assertSame(intent1, intents.getIntent("1"));
+		assertSame(intent2, intents.getIntent("2"));
+		assertSame(intent3, intents.getIntent("3"));
+
 		operations.clear();
-		operations.add(new IntentOperation(IntentOperation.Operator.REMOVE, intent4));
+		operations.add(Operator.ADD, intent4);
+		operations.add(Operator.ADD, intent5);
+		operations.add(Operator.ADD, intent6);
+		assertEquals(3, operations.size());
+
+		intents.executeOperations(operations);
+		assertEquals(4, intents.getAllIntents().size());
+		assertSame(intent4, intents.getIntent("1"));
+		assertSame(intent5, intents.getIntent("2"));
+		assertSame(intent3, intents.getIntent("3"));
+		assertSame(intent6, intents.getIntent("4"));
+	}
+
+	@Test
+	public void testRemoveOperation() {
+		IntentMap intents = new IntentMap();
+
+		Intent intent1 = new Intent("1");
+		ShortestPathIntent intent2 =
+				new ShortestPathIntent("2", 21L, 22L, 23L, 24L, 25L, 26L);
+		ConstrainedShortestPathIntent intent3 =
+				new ConstrainedShortestPathIntent("3", 31L, 32L, 33L, 34L, 35L, 36L, 1000.0);
+
+		IntentOperationList operations = new IntentOperationList();
+		operations.add(Operator.ADD, intent1);
+		operations.add(Operator.ADD, intent2);
+		operations.add(Operator.ADD, intent3);
+		intents.executeOperations(operations);
+		assertEquals(3, intents.getAllIntents().size());
+		assertSame(intent1, intents.getIntent("1"));
+		assertSame(intent2, intents.getIntent("2"));
+		assertSame(intent3, intents.getIntent("3"));
+
+		operations.clear();
+		operations.add(Operator.REMOVE, new Intent("1"));
+		operations.add(Operator.REMOVE, new Intent("3"));
+		intents.executeOperations(operations);
+		assertEquals(3, intents.getAllIntents().size());
+		assertSame(intent1, intents.getIntent("1"));
+		assertSame(intent2, intents.getIntent("2"));
+		assertSame(intent3, intents.getIntent("3"));
+		assertEquals(IntentState.DEL_REQ, intents.getIntent("1").getState());
+		assertEquals(IntentState.CREATED, intents.getIntent("2").getState());
+		assertEquals(IntentState.DEL_REQ, intents.getIntent("3").getState());
+	}
+
+	@Test
+	public void testErrorOperation() {
+		IntentMap intents = new IntentMap();
+		IntentOperationList operations = new IntentOperationList();
+		operations.add(Operator.ADD, new Intent("1", IntentState.CREATED));
+		operations.add(Operator.ADD, new Intent("2", IntentState.INST_REQ));
+		operations.add(Operator.ADD, new Intent("3", IntentState.INST_ACK));
+		operations.add(Operator.ADD, new Intent("4", IntentState.INST_NACK));
+		operations.add(Operator.ADD, new Intent("5", IntentState.REROUTE_REQ));
+		operations.add(Operator.ADD, new Intent("6", IntentState.DEL_REQ));
+		operations.add(Operator.ADD, new Intent("7", IntentState.DEL_ACK));
+		operations.add(Operator.ADD, new Intent("8", IntentState.DEL_PENDING));
+		intents.executeOperations(operations);
+		assertEquals(8, intents.getAllIntents().size());
+
+		operations.clear();
+		operations.add(Operator.ERROR, new ErrorIntent(ErrorType.PATH_NOT_FOUND, "", new Intent("1")));
+		operations.add(Operator.ERROR, new ErrorIntent(ErrorType.PATH_NOT_FOUND, "", new Intent("2")));
+		operations.add(Operator.ERROR, new ErrorIntent(ErrorType.PATH_NOT_FOUND, "", new Intent("3")));
+		operations.add(Operator.ERROR, new ErrorIntent(ErrorType.PATH_NOT_FOUND, "", new Intent("4")));
+		operations.add(Operator.ERROR, new ErrorIntent(ErrorType.PATH_NOT_FOUND, "", new Intent("5")));
+		operations.add(Operator.ERROR, new ErrorIntent(ErrorType.PATH_NOT_FOUND, "", new Intent("6")));
+		operations.add(Operator.ERROR, new ErrorIntent(ErrorType.PATH_NOT_FOUND, "", new Intent("7")));
+		operations.add(Operator.ERROR, new ErrorIntent(ErrorType.PATH_NOT_FOUND, "", new Intent("8")));
 		intents.executeOperations(operations);
 
-		// check
+		assertEquals(IntentState.INST_NACK, intents.getIntent("1").getState());
+		assertEquals(IntentState.INST_NACK, intents.getIntent("2").getState());
+		assertEquals(IntentState.INST_NACK, intents.getIntent("3").getState());
+		assertEquals(IntentState.INST_NACK, intents.getIntent("4").getState());
+		assertEquals(IntentState.INST_NACK, intents.getIntent("5").getState());
+		assertEquals(IntentState.DEL_PENDING, intents.getIntent("6").getState());
+		assertEquals(IntentState.DEL_ACK, intents.getIntent("7").getState());
+		assertEquals(IntentState.DEL_PENDING, intents.getIntent("8").getState());
+	}
 
-		assertEquals(3, intents.getAllIntents().size());
-		assertEquals(IntentState.DEL_REQ, intent1.getState());
-
-		// change intents' state which will be purged 
-
-		intent2.setState(IntentState.INST_NACK);
-		intent3.setState(IntentState.DEL_ACK);
-
-		// purge
+	@Test
+	public void testPurge() {
+		IntentMap intents = new IntentMap();
+		IntentOperationList operations = new IntentOperationList();
+		operations.add(Operator.ADD, new Intent("1", IntentState.CREATED));
+		operations.add(Operator.ADD, new Intent("2", IntentState.INST_REQ));
+		operations.add(Operator.ADD, new Intent("3", IntentState.INST_ACK));
+		operations.add(Operator.ADD, new Intent("4", IntentState.INST_NACK));
+		operations.add(Operator.ADD, new Intent("5", IntentState.REROUTE_REQ));
+		operations.add(Operator.ADD, new Intent("6", IntentState.DEL_REQ));
+		operations.add(Operator.ADD, new Intent("7", IntentState.DEL_ACK));
+		operations.add(Operator.ADD, new Intent("8", IntentState.DEL_PENDING));
+		intents.executeOperations(operations);
+		assertEquals(8, intents.getAllIntents().size());
 
 		intents.purge();
 
-		// check
+		assertEquals(6, intents.getAllIntents().size());
+		assertEquals("1", intents.getIntent("1").getId());
+		assertEquals("2", intents.getIntent("2").getId());
+		assertEquals("3", intents.getIntent("3").getId());
+		assertNull(intents.getIntent("4"));
+		assertEquals("5", intents.getIntent("5").getId());
+		assertEquals("6", intents.getIntent("6").getId());
+		assertNull("7", intents.getIntent("7"));
+		assertEquals("8", intents.getIntent("8").getId());
+	}
 
-		assertEquals(1, intents.getAllIntents().size());
-		assertEquals("1", intents.getAllIntents().iterator().next().getId());
+	@Test
+	public void testChangeStates() {
+		IntentMap intents = new IntentMap();
+		IntentOperationList operations = new IntentOperationList();
+		operations.add(Operator.ADD, new Intent("1", IntentState.CREATED));
+		operations.add(Operator.ADD, new Intent("2", IntentState.INST_REQ));
+		operations.add(Operator.ADD, new Intent("3", IntentState.INST_ACK));
+		operations.add(Operator.ADD, new Intent("4", IntentState.INST_NACK));
+		operations.add(Operator.ADD, new Intent("5", IntentState.REROUTE_REQ));
+		operations.add(Operator.ADD, new Intent("6", IntentState.DEL_REQ));
+		operations.add(Operator.ADD, new Intent("7", IntentState.DEL_ACK));
+		operations.add(Operator.ADD, new Intent("8", IntentState.DEL_PENDING));
+		intents.executeOperations(operations);
+		assertEquals(8, intents.getAllIntents().size());
+
+		IntentStateList states = new IntentStateList();
+		states.put("8", IntentState.CREATED);
+		states.put("1", IntentState.INST_REQ);
+		states.put("2", IntentState.INST_ACK);
+		states.put("3", IntentState.INST_NACK);
+		states.put("4", IntentState.REROUTE_REQ);
+		states.put("5", IntentState.DEL_REQ);
+		states.put("6", IntentState.DEL_ACK);
+		states.put("7", IntentState.DEL_PENDING);
+		intents.changeStates(states);
+
+		assertEquals(IntentState.INST_REQ, intents.getIntent("1").getState());
+		assertEquals(IntentState.INST_ACK, intents.getIntent("2").getState());
+		assertEquals(IntentState.INST_NACK, intents.getIntent("3").getState());
+		assertEquals(IntentState.REROUTE_REQ, intents.getIntent("4").getState());
+		assertEquals(IntentState.DEL_REQ, intents.getIntent("5").getState());
+		assertEquals(IntentState.DEL_ACK, intents.getIntent("6").getState());
+		assertEquals(IntentState.DEL_PENDING, intents.getIntent("7").getState());
+		assertEquals(IntentState.CREATED, intents.getIntent("8").getState());
 	}
 }
diff --git a/src/test/java/net/onrc/onos/intent/IntentOperationListTest.java b/src/test/java/net/onrc/onos/intent/IntentOperationListTest.java
index ad5315b..e0e907f 100644
--- a/src/test/java/net/onrc/onos/intent/IntentOperationListTest.java
+++ b/src/test/java/net/onrc/onos/intent/IntentOperationListTest.java
@@ -13,6 +13,9 @@
 import com.esotericsoftware.kryo.io.Input;
 import com.esotericsoftware.kryo.io.Output;
 
+/**
+ * @author Toshio Koide (t-koide@onlab.us)
+ */
 public class IntentOperationListTest {
 
 	@Before
diff --git a/src/test/java/net/onrc/onos/intent/MockNetworkGraph.java b/src/test/java/net/onrc/onos/intent/MockNetworkGraph.java
index a8f928a..5ae7b13 100644
--- a/src/test/java/net/onrc/onos/intent/MockNetworkGraph.java
+++ b/src/test/java/net/onrc/onos/intent/MockNetworkGraph.java
@@ -8,6 +8,9 @@
 import net.onrc.onos.ofcontroller.networkgraph.Switch;
 import net.onrc.onos.ofcontroller.networkgraph.SwitchImpl;
 
+/**
+ * @author Toshio Koide (t-koide@onlab.us)
+ */
 public class MockNetworkGraph extends NetworkGraphImpl {
 	class DetachableLinkImpl extends LinkImpl {
 		public DetachableLinkImpl(NetworkGraph graph, Port srcPort, Port dstPort) {
@@ -16,7 +19,7 @@
 
 		public void detachFromGraph() {
 			unsetFromPorts();
-		}	
+		}
 	}
 	public Switch addSwitch(Long switchId) {
 		SwitchImpl sw = new SwitchImpl(this, switchId);
@@ -39,7 +42,7 @@
 
 		return links;
 	}
-	
+
 	public void createSampleTopology() {
 		// add 10 switches (24 ports switch)
 		for (Long dpid=1L; dpid<10L; dpid++) {
diff --git a/src/test/java/net/onrc/onos/intent/PathIntentTest.java b/src/test/java/net/onrc/onos/intent/PathIntentTest.java
index 3c76f3f..211a68a 100644
--- a/src/test/java/net/onrc/onos/intent/PathIntentTest.java
+++ b/src/test/java/net/onrc/onos/intent/PathIntentTest.java
@@ -14,6 +14,9 @@
 import com.esotericsoftware.kryo.io.Input;
 import com.esotericsoftware.kryo.io.Output;
 
+/**
+ * @author Toshio Koide (t-koide@onlab.us)
+ */
 public class PathIntentTest {
 	NetworkGraph g;
 
diff --git a/src/test/java/net/onrc/onos/intent/ShortestPathIntentTest.java b/src/test/java/net/onrc/onos/intent/ShortestPathIntentTest.java
index e325be8..e118b66 100644
--- a/src/test/java/net/onrc/onos/intent/ShortestPathIntentTest.java
+++ b/src/test/java/net/onrc/onos/intent/ShortestPathIntentTest.java
@@ -11,6 +11,9 @@
 import com.esotericsoftware.kryo.io.Input;
 import com.esotericsoftware.kryo.io.Output;
 
+/**
+ * @author Toshio Koide (t-koide@onlab.us)
+ */
 public class ShortestPathIntentTest {
 	NetworkGraph g;
 
diff --git a/src/test/java/net/onrc/onos/intent/runtime/UseCaseTest.java b/src/test/java/net/onrc/onos/intent/runtime/UseCaseTest.java
index 00da877..cb4ab9e 100755
--- a/src/test/java/net/onrc/onos/intent/runtime/UseCaseTest.java
+++ b/src/test/java/net/onrc/onos/intent/runtime/UseCaseTest.java
@@ -1,6 +1,7 @@
 package net.onrc.onos.intent.runtime;
 
-import java.util.HashMap;
+import static org.easymock.EasyMock.*;
+
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Set;
@@ -9,12 +10,12 @@
 import net.floodlightcontroller.core.module.FloodlightModuleException;
 import net.onrc.onos.datagrid.IDatagridService;
 import net.onrc.onos.datagrid.IEventChannel;
+import net.onrc.onos.datagrid.IEventChannelListener;
 import net.onrc.onos.intent.ConstrainedShortestPathIntent;
 import net.onrc.onos.intent.FlowEntry;
 import net.onrc.onos.intent.Intent;
 import net.onrc.onos.intent.Intent.IntentState;
 import net.onrc.onos.intent.IntentOperation.Operator;
-import net.onrc.onos.intent.IntentOperation;
 import net.onrc.onos.intent.IntentOperationList;
 import net.onrc.onos.intent.MockNetworkGraph;
 import net.onrc.onos.intent.PathIntent;
@@ -30,7 +31,6 @@
 import net.onrc.onos.ofcontroller.networkgraph.SwitchEvent;
 import net.onrc.onos.registry.controller.IControllerRegistryService;
 
-import org.easymock.EasyMock;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -61,47 +61,54 @@
 		graph.createSampleTopology();
 		g = graph;
 
-		datagridService = EasyMock.createMock(IDatagridService.class);
-		networkGraphService = EasyMock.createMock(INetworkGraphService.class);
-		controllerRegistryService = EasyMock.createMock(IControllerRegistryService.class);
-		modContext = EasyMock.createMock(FloodlightModuleContext.class);
-		eventChannel = EasyMock.createMock(IEventChannel.class);
+		datagridService = createMock(IDatagridService.class);
+		networkGraphService = createMock(INetworkGraphService.class);
+		controllerRegistryService = createMock(IControllerRegistryService.class);
+		modContext = createMock(FloodlightModuleContext.class);
+		eventChannel = createMock(IEventChannel.class);
 		persistIntent = PowerMock.createMock(PersistIntent.class);
 
 		PowerMock.expectNew(PersistIntent.class,
-				EasyMock.anyObject(IControllerRegistryService.class),
-				EasyMock.anyObject(INetworkGraphService.class)).andReturn(persistIntent);
+				anyObject(IControllerRegistryService.class),
+				anyObject(INetworkGraphService.class)).andReturn(persistIntent);
 
-		EasyMock.expect(modContext.getServiceImpl(EasyMock.eq(IDatagridService.class)))
+		expect(modContext.getServiceImpl(IDatagridService.class))
 		.andReturn(datagridService).once();
-		EasyMock.expect(modContext.getServiceImpl(EasyMock.eq(INetworkGraphService.class)))
+		expect(modContext.getServiceImpl(INetworkGraphService.class))
 		.andReturn(networkGraphService).once();
-		EasyMock.expect(modContext.getServiceImpl(EasyMock.eq(IControllerRegistryService.class)))
+		expect(modContext.getServiceImpl(IControllerRegistryService.class))
 		.andReturn(controllerRegistryService).once();
-		EasyMock.expect(persistIntent.getKey()).andReturn(1L).anyTimes();
-		EasyMock.expect(persistIntent.persistIfLeader(EasyMock.eq(1L),
-				EasyMock.anyObject(IntentOperationList.class))).andReturn(true).anyTimes();
+		expect(persistIntent.getKey()).andReturn(1L).anyTimes();
+		expect(persistIntent.persistIfLeader(eq(1L),
+				anyObject(IntentOperationList.class))).andReturn(true).anyTimes();
 
-		EasyMock.expect(networkGraphService.getNetworkGraph()).andReturn(g).anyTimes();
-		networkGraphService.registerNetworkGraphListener(EasyMock.anyObject(INetworkGraphListener.class));
-		EasyMock.expectLastCall();
+		expect(networkGraphService.getNetworkGraph()).andReturn(g).anyTimes();
+		networkGraphService.registerNetworkGraphListener(anyObject(INetworkGraphListener.class));
+		expectLastCall();
 
-		EasyMock.expect(datagridService.createChannel("onos.pathintent", Long.class, IntentOperationList.class))
+		expect(datagridService.createChannel("onos.pathintent", Long.class, IntentOperationList.class))
 		.andReturn(eventChannel).once();
 
-		EasyMock.replay(datagridService);
-		EasyMock.replay(networkGraphService);
-		EasyMock.replay(modContext);
-		EasyMock.replay(controllerRegistryService);
+		expect(datagridService.addListener(
+				eq("onos.pathintent_state"),
+				anyObject(IEventChannelListener.class),
+				eq(Long.class),
+				eq(IntentStateList.class)))
+		.andReturn(eventChannel).once();
+
+		replay(datagridService);
+		replay(networkGraphService);
+		replay(modContext);
+		replay(controllerRegistryService);
 		PowerMock.replay(persistIntent, PersistIntent.class);
 	}
 
 	@After
 	public void tearDown() {
-		EasyMock.verify(datagridService);
-		EasyMock.verify(networkGraphService);
-		EasyMock.verify(modContext);
-		EasyMock.verify(controllerRegistryService);
+		verify(datagridService);
+		verify(networkGraphService);
+		verify(modContext);
+		verify(controllerRegistryService);
 		PowerMock.verify(persistIntent, PersistIntent.class);
 	}
 
@@ -221,7 +228,7 @@
 		System.out.println(plan);
 
 		// TODO this state changes should be triggered by notification of plan module
-		HashMap<String, IntentState> states = new HashMap<>();
+		IntentStateList states = new IntentStateList();
 		states.put("1", IntentState.INST_ACK);
 		states.put("2", IntentState.INST_ACK);
 		states.put("3", IntentState.INST_ACK);