@Test
public void testAddHost() {

    testModifyNetwork();
    vns.addHost(mac1, guid1, hostPort1);
    assertTrue(vns.macToGuid.get(mac1).equals(guid1));
    assertTrue(vns.portToMac.get(hostPort1).equals(mac1));
    assertTrue(vns.vNetsByGuid.get(guid1).portToMac.containsValue(mac1));
    vns.addHost(mac2, guid1, hostPort2);
    assertTrue(vns.macToGuid.get(mac2).equals(guid1));
    assertTrue(vns.portToMac.get(hostPort2).equals(mac2));
    assertTrue(vns.vNetsByGuid.get(guid1).portToMac.containsValue(mac2));
    vns.addHost(mac3, guid3, hostPort3);
    vns.addHost(mac4, guid3, hostPort4);
    assertTrue(vns.vNetsByGuid.get(guid3).portToMac.containsValue(mac4));
}