diff --git a/utils/misc/src/test/java/org/onlab/util/ToolsTest.java b/utils/misc/src/test/java/org/onlab/util/ToolsTest.java
index cfa0200592..ab6a7ee979 100644
--- a/utils/misc/src/test/java/org/onlab/util/ToolsTest.java
+++ b/utils/misc/src/test/java/org/onlab/util/ToolsTest.java
@@ -47,6 +47,7 @@ public class ToolsTest {
         assertEquals("1000", Tools.toHex(4096, 4));
         assertEquals("000000000000000f", Tools.toHex(15));
         assertEquals("ffffffffffffffff", Tools.toHex(0xffffffffffffffffL));
+        assertEquals("0xffffffffffffffff", Tools.toHexWithPrefix(0xffffffffffffffffL));
 
     }