Unit tests for AtomicValueEvent and SetEvent

Change-Id: I44562365f3076b7cc1afaf5cef9e5be584b432e9
diff --git a/core/api/src/main/java/org/onosproject/store/service/AtomicValueEvent.java b/core/api/src/main/java/org/onosproject/store/service/AtomicValueEvent.java
index 226b164..1bce136 100644
--- a/core/api/src/main/java/org/onosproject/store/service/AtomicValueEvent.java
+++ b/core/api/src/main/java/org/onosproject/store/service/AtomicValueEvent.java
@@ -24,7 +24,7 @@
  *
  * @param <V> atomic value type
  */
-public class AtomicValueEvent<V> {
+public final class AtomicValueEvent<V> {
 
     /**
      * AtomicValueEvent type.
@@ -87,7 +87,7 @@
             return false;
         }
 
-        AtomicValueEvent<V> that = (AtomicValueEvent) o;
+        AtomicValueEvent that = (AtomicValueEvent) o;
         return Objects.equals(this.name, that.name) &&
                 Objects.equals(this.type, that.type) &&
                 Objects.equals(this.value, that.value);
@@ -106,4 +106,4 @@
                 .add("value", value)
                 .toString();
     }
-}
\ No newline at end of file
+}