Started to work on topology abstraction.
Added more unit tests.
Changed mastership application to be synchronous.
diff --git a/net/api/src/test/java/org/onlab/onos/net/DefaultEdgeLinkTest.java b/net/api/src/test/java/org/onlab/onos/net/DefaultEdgeLinkTest.java
new file mode 100644
index 0000000..368ff16
--- /dev/null
+++ b/net/api/src/test/java/org/onlab/onos/net/DefaultEdgeLinkTest.java
@@ -0,0 +1,58 @@
+package org.onlab.onos.net;
+
+import com.google.common.testing.EqualsTester;
+import org.junit.Test;
+import org.onlab.onos.net.provider.ProviderId;
+
+import static org.junit.Assert.assertEquals;
+import static org.onlab.onos.net.DefaultLinkTest.cp;
+import static org.onlab.onos.net.DeviceId.deviceId;
+import static org.onlab.onos.net.HostId.hostId;
+import static org.onlab.onos.net.PortNumber.portNumber;
+
+/**
+ * Test of the default edge link model entity.
+ */
+public class DefaultEdgeLinkTest {
+
+    private static final ProviderId PID = new ProviderId("foo");
+    private static final DeviceId DID1 = deviceId("of:foo");
+    private static final HostId HID1 = hostId("nic:foobar");
+    private static final HostId HID2 = hostId("nic:barfoo");
+    private static final PortNumber P0 = portNumber(0);
+    private static final PortNumber P1 = portNumber(1);
+
+    @Test
+    public void testEquality() {
+        EdgeLink l1 = new DefaultEdgeLink(PID, cp(HID1, P0),
+                                          new HostLocation(DID1, P1, 123L), true);
+        EdgeLink l2 = new DefaultEdgeLink(PID, cp(HID1, P0),
+                                          new HostLocation(DID1, P1, 123L), true);
+
+        EdgeLink l3 = new DefaultEdgeLink(PID, cp(HID2, P0),
+                                          new HostLocation(DID1, P1, 123L), false);
+        EdgeLink l4 = new DefaultEdgeLink(PID, cp(HID2, P0),
+                                          new HostLocation(DID1, P1, 123L), false);
+
+        EdgeLink l5 = new DefaultEdgeLink(PID, cp(HID1, P0),
+                                          new HostLocation(DID1, P1, 123L), false);
+
+        new EqualsTester().addEqualityGroup(l1, l2)
+                .addEqualityGroup(l3, l4)
+                .addEqualityGroup(l5)
+                .testEquals();
+    }
+
+    @Test
+    public void basics() {
+        HostLocation hostLocation = new HostLocation(DID1, P1, 123L);
+        EdgeLink link = new DefaultEdgeLink(PID, cp(HID1, P0), hostLocation, false);
+        assertEquals("incorrect src", cp(HID1, P0), link.src());
+        assertEquals("incorrect dst", hostLocation, link.dst());
+        assertEquals("incorrect type", Link.Type.EDGE, link.type());
+        assertEquals("incorrect hostId", HID1, link.hostId());
+        assertEquals("incorrect connect point", hostLocation, link.hostLocation());
+        assertEquals("incorrect time", 123L, link.hostLocation().time());
+    }
+
+}
diff --git a/net/api/src/test/java/org/onlab/onos/net/DefaultLinkTest.java b/net/api/src/test/java/org/onlab/onos/net/DefaultLinkTest.java
index 37757af..ec8511e 100644
--- a/net/api/src/test/java/org/onlab/onos/net/DefaultLinkTest.java
+++ b/net/api/src/test/java/org/onlab/onos/net/DefaultLinkTest.java
@@ -21,7 +21,7 @@
     private static final PortNumber P1 = portNumber(1);
     private static final PortNumber P2 = portNumber(2);
 
-    public static ConnectPoint cp(DeviceId id, PortNumber pn) {
+    public static ConnectPoint cp(ElementId id, PortNumber pn) {
         return new ConnectPoint(id, pn);
     }
 
diff --git a/net/api/src/test/java/org/onlab/onos/net/DefaultPortTest.java b/net/api/src/test/java/org/onlab/onos/net/DefaultPortTest.java
new file mode 100644
index 0000000..e9d3da6
--- /dev/null
+++ b/net/api/src/test/java/org/onlab/onos/net/DefaultPortTest.java
@@ -0,0 +1,47 @@
+package org.onlab.onos.net;
+
+import com.google.common.testing.EqualsTester;
+import org.junit.Test;
+import org.onlab.onos.net.provider.ProviderId;
+
+import static org.junit.Assert.assertEquals;
+import static org.onlab.onos.net.Device.Type.SWITCH;
+import static org.onlab.onos.net.DeviceId.deviceId;
+import static org.onlab.onos.net.PortNumber.portNumber;
+
+/**
+ * Test of the default port model entity.
+ */
+public class DefaultPortTest {
+
+    private static final ProviderId PID = new ProviderId("foo");
+    private static final DeviceId DID1 = deviceId("of:foo");
+    private static final DeviceId DID2 = deviceId("of:bar");
+    private static final PortNumber P1 = portNumber(1);
+    private static final PortNumber P2 = portNumber(2);
+
+    @Test
+    public void testEquality() {
+        Device device = new DefaultDevice(PID, DID1, SWITCH, "m", "h", "s", "n");
+        Port p1 = new DefaultPort(device, portNumber(1), true);
+        Port p2 = new DefaultPort(device, portNumber(1), true);
+        Port p3 = new DefaultPort(device, portNumber(2), true);
+        Port p4 = new DefaultPort(device, portNumber(2), true);
+        Port p5 = new DefaultPort(device, portNumber(1), false);
+
+        new EqualsTester().addEqualityGroup(p1, p2)
+                .addEqualityGroup(p3, p4)
+                .addEqualityGroup(p5)
+                .testEquals();
+    }
+
+    @Test
+    public void basics() {
+        Device device = new DefaultDevice(PID, DID1, SWITCH, "m", "h", "s", "n");
+        Port port = new DefaultPort(device, portNumber(1), true);
+        assertEquals("incorrect element", device, port.element());
+        assertEquals("incorrect number", portNumber(1), port.number());
+        assertEquals("incorrect state", true, port.isEnabled());
+    }
+
+}
diff --git a/net/api/src/test/java/org/onlab/onos/net/HostIdTest.java b/net/api/src/test/java/org/onlab/onos/net/HostIdTest.java
new file mode 100644
index 0000000..3adcabc
--- /dev/null
+++ b/net/api/src/test/java/org/onlab/onos/net/HostIdTest.java
@@ -0,0 +1,22 @@
+package org.onlab.onos.net;
+
+import com.google.common.testing.EqualsTester;
+import org.junit.Test;
+
+import static org.onlab.onos.net.HostId.hostId;
+
+/**
+ * Test of the host identifier.
+ */
+public class HostIdTest extends ElementIdTest {
+
+    @Test
+    public void basics() {
+        new EqualsTester()
+                .addEqualityGroup(hostId("nic:foo"),
+                                  hostId("nic:foo"))
+                .addEqualityGroup(hostId("nic:bar"))
+                .testEquals();
+    }
+
+}