Unit tests for DefaultGroupDescription class

Change-Id: Ic1378e9be3067bd45def74769023d51178765260
diff --git a/core/api/src/main/java/org/onosproject/net/group/DefaultGroupDescription.java b/core/api/src/main/java/org/onosproject/net/group/DefaultGroupDescription.java
index a5b8e94..1580d83 100644
--- a/core/api/src/main/java/org/onosproject/net/group/DefaultGroupDescription.java
+++ b/core/api/src/main/java/org/onosproject/net/group/DefaultGroupDescription.java
@@ -181,7 +181,7 @@
         if (this == obj) {
             return true;
         }
-       if (obj instanceof DefaultGroupDescription) {
+        if (obj instanceof DefaultGroupDescription) {
             DefaultGroupDescription that = (DefaultGroupDescription) obj;
             return Objects.equals(deviceId, that.deviceId) &&
                     Objects.equals(type, that.type) &&
@@ -201,4 +201,4 @@
                 .add("givenGroupId", givenGroupId)
                 .toString();
     }
-}
\ No newline at end of file
+}