Unit tests for PartitionManager

Change-Id: I721ed6489ce19cb78ce9e2f150dfed90882f3b0e
diff --git a/core/store/dist/src/main/java/org/onosproject/store/intent/impl/PartitionManager.java b/core/store/dist/src/main/java/org/onosproject/store/intent/impl/PartitionManager.java
index 72590aa..36475b8 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/intent/impl/PartitionManager.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/intent/impl/PartitionManager.java
@@ -57,7 +57,7 @@
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     protected ClusterService clusterService;
 
-    private static final int NUM_PARTITIONS = 14;
+    static final int NUM_PARTITIONS = 14;
     private static final int BACKOFF_TIME = 2;
     private static final int CHECK_PERIOD = 10;
 
@@ -90,6 +90,17 @@
         clusterService.removeListener(clusterListener);
     }
 
+    /**
+     * Sets the specified executor to be used for scheduling background tasks.
+     *
+     * @param executor scheduled executor service for background tasks
+     * @return this PartitionManager
+     */
+    public PartitionManager withScheduledExecutor(ScheduledExecutorService executor) {
+        this.executor = executor;
+        return this;
+    }
+
     private String getPartitionPath(int i) {
         return ELECTION_PREFIX + i;
     }