[ONOS-7683] Add unit tests for a set of telemetry config classes

Change-Id: I73ad36e02044371a2fb87540e28ef2257a6dba92
diff --git a/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/config/GrpcTelemetryConfig.java b/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/config/GrpcTelemetryConfig.java
index 56a364e..d7c8f62 100644
--- a/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/config/GrpcTelemetryConfig.java
+++ b/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/config/GrpcTelemetryConfig.java
@@ -20,7 +20,7 @@
 /**
  * Configuration API of gRPC for publishing openstack telemetry.
  */
-public interface GrpcTelemetryConfig {
+public interface GrpcTelemetryConfig extends TelemetryConfig {
 
     /**
      * Obtains gRPC server IP address.
@@ -60,7 +60,7 @@
     /**
      * Builder class of GrpcTelemetryConfig.
      */
-    interface Builder {
+    interface Builder extends TelemetryConfig.Builder {
 
         /**
          * Sets gRPC server IP address.
diff --git a/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/config/InfluxDbTelemetryConfig.java b/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/config/InfluxDbTelemetryConfig.java
index f0c34ca..de8a36f 100644
--- a/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/config/InfluxDbTelemetryConfig.java
+++ b/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/config/InfluxDbTelemetryConfig.java
@@ -20,7 +20,7 @@
 /**
  * Configuration API of InfluxDB for publishing openstack telemetry.
  */
-public interface InfluxDbTelemetryConfig {
+public interface InfluxDbTelemetryConfig extends TelemetryConfig {
 
     /**
      * Obtains InfluxDB server IP address.
@@ -74,7 +74,7 @@
     /**
      * Builder class of InfluxDbTelemetryConfig.
      */
-    interface Builder {
+    interface Builder extends TelemetryConfig.Builder {
 
         /**
          * Sets InfluxDB server IP address.
diff --git a/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/config/KafkaTelemetryConfig.java b/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/config/KafkaTelemetryConfig.java
index d3731bb..078433f 100644
--- a/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/config/KafkaTelemetryConfig.java
+++ b/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/config/KafkaTelemetryConfig.java
@@ -20,7 +20,7 @@
 /**
  * Configuration API of Kafka for publishing openstack telemetry.
  */
-public interface KafkaTelemetryConfig {
+public interface KafkaTelemetryConfig extends TelemetryConfig {
 
     /**
      * Obtains kafka IP address.
@@ -95,7 +95,7 @@
     /**
      * Builder class of KafkaTelemetryConfig.
      */
-    interface Builder {
+    interface Builder extends TelemetryConfig.Builder {
 
         /**
          * Sets kafka IP address.
diff --git a/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/config/RestTelemetryConfig.java b/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/config/RestTelemetryConfig.java
index 50643db2..0e9add5 100644
--- a/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/config/RestTelemetryConfig.java
+++ b/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/config/RestTelemetryConfig.java
@@ -20,7 +20,7 @@
 /**
  * Configuration API of REST for publishing openstack telemetry.
  */
-public interface RestTelemetryConfig {
+public interface RestTelemetryConfig extends TelemetryConfig {
 
     /**
      * Obtains REST IP address.
@@ -74,7 +74,7 @@
     /**
      * Builder class for RestTelemetryConfig.
      */
-    interface Builder {
+    interface Builder extends TelemetryConfig.Builder {
 
         /**
          * Sets REST server IP address.
diff --git a/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/config/TelemetryConfig.java b/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/config/TelemetryConfig.java
new file mode 100644
index 0000000..1d31c86
--- /dev/null
+++ b/apps/openstacktelemetry/api/src/main/java/org/onosproject/openstacktelemetry/api/config/TelemetryConfig.java
@@ -0,0 +1,27 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+ *
+ * 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.onosproject.openstacktelemetry.api.config;
+
+/**
+ * An interface for telemetryconfig.
+ */
+public interface TelemetryConfig {
+
+    Builder createBuilder();
+
+    interface Builder {
+    }
+}