[ONOS-6062] Unit Test for Json Serializer

1. Add Unit Test cases for Json Serializer.
2. Resolved issues during Unit Test.

Change-Id: If7a12607ed88cae38e972e885cb3db2e9e440e2b
diff --git a/serializers/json/pom.xml b/serializers/json/pom.xml
index f14f010..b8ce21e 100644
--- a/serializers/json/pom.xml
+++ b/serializers/json/pom.xml
@@ -61,4 +61,31 @@
             <version>RELEASE</version>
         </dependency>
     </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.onosproject</groupId>
+                <artifactId>onos-yang-compiler-maven-plugin</artifactId>
+                <version>${project.version}</version>
+                <configuration>
+                    <yangFilesDir>src/test/resources</yangFilesDir>
+                </configuration>
+                <executions>
+                    <execution>
+                        <id>default</id>
+                        <goals>
+                            <goal>yang2java</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.felix</groupId>
+                <artifactId>maven-bundle-plugin</artifactId>
+                <version>3.2.0</version>
+                <extensions>true</extensions>
+            </plugin>
+        </plugins>
+    </build>
 </project>