ONOS-792 Implement Unit Tests for Links and Devices REST APIs

Also added a missing attribute to the Devices codec

Change-Id: I824a3559ca6278297a52169249f413c850204a9b

@@ -33,12 +33,14 @@ public class DeviceCodec extends AnnotatedCodec<Device> {
         DeviceService service = context.get(DeviceService.class);
         ObjectNode result = context.mapper().createObjectNode()
                 .put("id", device.id().toString())
+                .put("type", device.type().name())
                 .put("available", service.isAvailable(device.id()))
                 .put("role", service.getRole(device.id()).toString())
                 .put("mfr", device.manufacturer())
                 .put("hw", device.hwVersion())
                 .put("sw", device.swVersion())
-                .put("serial", device.serialNumber());
+                .put("serial", device.serialNumber())
+                .put("chassisId", device.chassisId().toString());
         return annotate(result, device, context);
     }