[ONOS-3222] Implement toString method for each Packet class

Change-Id: I17d72338d4202117d08b3dca9463be35a87a0c1e
diff --git a/utils/misc/src/test/java/org/onlab/packet/MplsTest.java b/utils/misc/src/test/java/org/onlab/packet/MplsTest.java
index 2ab8ff9..b08b2e9 100644
--- a/utils/misc/src/test/java/org/onlab/packet/MplsTest.java
+++ b/utils/misc/src/test/java/org/onlab/packet/MplsTest.java
@@ -16,6 +16,7 @@
 
 package org.onlab.packet;
 
+import org.apache.commons.lang3.StringUtils;
 import org.junit.Before;
 import org.junit.Test;
 
@@ -23,6 +24,7 @@
 import java.util.HashMap;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
 
 /**
  * Unit tests for MPLS class.
@@ -62,6 +64,9 @@
         PacketTestUtils.testDeserializeTruncated(deserializer, bytes);
     }
 
+    /**
+     * Tests deserialize and getters.
+     */
     @Test
     public void testDeserialize() throws Exception {
         MPLS mpls = deserializer.deserialize(bytes, 0, bytes.length);
@@ -71,4 +76,18 @@
         assertEquals(ttl, mpls.ttl);
         assertEquals(protocol, mpls.protocol);
     }
+
+    /**
+     * Tests toString.
+     */
+    @Test
+    public void testToStringMpls() throws Exception {
+        MPLS mpls = deserializer.deserialize(bytes, 0, bytes.length);
+        String str = mpls.toString();
+
+        assertTrue(StringUtils.contains(str, "label=" + label));
+        assertTrue(StringUtils.contains(str, "bos=" + bos));
+        assertTrue(StringUtils.contains(str, "ttl=" + ttl));
+        assertTrue(StringUtils.contains(str, "protocol=" + protocol));
+    }
 }