Add /0 netmask check

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/net/branches/NET_2_0@761985 13f79535-47bb-0310-9956-ffa450edef68

Author: Rory Winston

src/test/java/org/apache/commons/net/SubnetUtilsTest.java

@@ -58,4 +58,14 @@ public void testAddresses() {
         assertFalse(info.isInRange("192.168.1.1"));
         assertFalse(info.isInRange("192.168.0.255"));
     }
+    
+    public void testZeroNetmaskBits() {
+    	try {
+    		SubnetUtils utils = new SubnetUtils("192.168.0.1/0");
+    		assertTrue("/0 should be an invalid mask", false);
+    	}
+    	catch (Exception e) {
+    		;
+    	}
+    }
 }