Enhance StatisticService to allow filtering by Application ID and Group ID

Resolve ONOS-205

Change-Id: Ie9318a5ade943bd8e47fb92ee856b7ebead5022e
diff --git a/core/api/src/test/java/org/onlab/onos/core/DefaultGroupIdTest.java b/core/api/src/test/java/org/onlab/onos/core/DefaultGroupIdTest.java
new file mode 100644
index 0000000..53b3d2c
--- /dev/null
+++ b/core/api/src/test/java/org/onlab/onos/core/DefaultGroupIdTest.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.onos.core;
+
+import com.google.common.testing.EqualsTester;
+import org.junit.Test;
+
+/**
+ * Test for DefaultGroupId.
+ */
+public class DefaultGroupIdTest {
+
+    /**
+     * Tests the equality of the instances.
+     */
+    @Test
+    public void testEquality() {
+        DefaultGroupId id1 = new DefaultGroupId((short) 1);
+        DefaultGroupId id2 = new DefaultGroupId((short) 1);
+        DefaultGroupId id3 = new DefaultGroupId((short) 2);
+
+        new EqualsTester()
+                .addEqualityGroup(id1, id2)
+                .addEqualityGroup(id3)
+                .testEquals();
+    }
+
+}