Adding more unit tests.
Made some classes abstract which should have been.
diff --git a/core/api/src/main/java/org/onlab/onos/net/AbstractModel.java b/core/api/src/main/java/org/onlab/onos/net/AbstractModel.java
index 482ec68..f5f7689 100644
--- a/core/api/src/main/java/org/onlab/onos/net/AbstractModel.java
+++ b/core/api/src/main/java/org/onlab/onos/net/AbstractModel.java
@@ -5,7 +5,7 @@
/**
* Base implementation of a network model entity.
*/
-public class AbstractModel extends AbstractAnnotated implements Provided {
+public abstract class AbstractModel extends AbstractAnnotated implements Provided {
private final ProviderId providerId;