diff --git a/java_gen/pre-written/src/test/java/org/projectfloodlight/openflow/types/IPv6AddressTest.java b/java_gen/pre-written/src/test/java/org/projectfloodlight/openflow/types/IPv6AddressTest.java
index da31470..6963c21 100644
--- a/java_gen/pre-written/src/test/java/org/projectfloodlight/openflow/types/IPv6AddressTest.java
+++ b/java_gen/pre-written/src/test/java/org/projectfloodlight/openflow/types/IPv6AddressTest.java
@@ -305,5 +305,13 @@
         } catch (NullPointerException e) {
             assertNotNull(e.getMessage());
         }
+        try {
+            IPv6AddressWithMask.of(IPv6Address.of("10:10::0"),
+                                   IPv6Address.of("ffff:0:ffff::"))
+                                   .getSubnetBroadcastAddress();
+            fail("Should have thrown IllegalArgumentException");
+        } catch (IllegalArgumentException e) {
+            assertNotNull(e.getMessage());
+        }
     }
 }