diff --git a/utils/misc/src/test/java/org/onlab/packet/MacAddressTest.java b/utils/misc/src/test/java/org/onlab/packet/MacAddressTest.java
index 38a3b43..468107e 100644
--- a/utils/misc/src/test/java/org/onlab/packet/MacAddressTest.java
+++ b/utils/misc/src/test/java/org/onlab/packet/MacAddressTest.java
@@ -46,6 +46,10 @@
 
     private static final String INVALID_STR = "invalid";
     private static final byte[] INVALID_BYTE = {(byte) 0xaa};
+    private static final String INVALID_MAC_ADDITIONAL_COLON = "00:00:00:00:00:00:";
+    private static final String INVALID_MAC_OCTET_TOO_LONG = "000:000:000:000:000:00";
+    private static final String INVALID_MAC_OCTET_TOO_SHORT = "00:0:00:00:00:00";
+
 
     @Test
     public void testValueOfString() throws Exception {
@@ -57,6 +61,21 @@
         MacAddress.valueOf(INVALID_STR);
     }
 
+    @Test(expected = IllegalArgumentException.class)
+    public void testValueOfInvalidStringWithAdditionalColon() throws Exception {
+        MacAddress.valueOf(INVALID_MAC_ADDITIONAL_COLON);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testValueOfInvalidStringWithTooLongOctet() throws Exception {
+        MacAddress.valueOf(INVALID_MAC_OCTET_TOO_LONG);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testValueOfInvalidStringWithTooShortOctet() throws Exception {
+        MacAddress.valueOf(INVALID_MAC_OCTET_TOO_SHORT);
+    }
+
     @Test
     public void testValueOfByte() throws Exception {
         assertArrayEquals(MAC_ONOS_BYTE, MacAddress.valueOf(MAC_ONOS_BYTE).toBytes());