Fix bug of Resource#isSubTypeOf() and improve unit test coverage

Change-Id: I5488c1065a8f83abb110ad67276c30eb719ccd01
diff --git a/core/api/src/test/java/org/onosproject/net/newresource/DiscreteResourceTest.java b/core/api/src/test/java/org/onosproject/net/newresource/DiscreteResourceTest.java
index 0001c70..612ef1a 100644
--- a/core/api/src/test/java/org/onosproject/net/newresource/DiscreteResourceTest.java
+++ b/core/api/src/test/java/org/onosproject/net/newresource/DiscreteResourceTest.java
@@ -76,6 +76,7 @@
     @Test
     public void testTypeOf() {
         DiscreteResource discrete = Resources.discrete(D1, P1, VLAN1).resource();
+
         assertThat(discrete.isTypeOf(DeviceId.class), is(false));
         assertThat(discrete.isTypeOf(PortNumber.class), is(false));
         assertThat(discrete.isTypeOf(VlanId.class), is(true));
@@ -84,6 +85,7 @@
     @Test
     public void testSubTypeOf() {
         DiscreteResource discrete = Resources.discrete(D1, P1, VLAN1).resource();
+
         assertThat(discrete.isSubTypeOf(DeviceId.class), is(true));
         assertThat(discrete.isSubTypeOf(PortNumber.class), is(true));
         assertThat(discrete.isSubTypeOf(VlanId.class), is(true));
@@ -91,6 +93,13 @@
     }
 
     @Test
+    public void testSubTypeOfObject() {
+        DiscreteResource discrete = Resources.discrete(D1, P1, VLAN1).resource();
+
+        assertThat(discrete.isSubTypeOf(Object.class), is(true));
+    }
+
+    @Test
     public void testValueAs() {
         DiscreteResource resource = Resources.discrete(D1).resource();