LAST_INDEX_OF lastIndexOf = new LAST_INDEX_OF();
Tuple testTuple = Util.buildTuple("xyz", "");
assertEquals( ((Integer) "xyz".lastIndexOf("")), lastIndexOf.exec(testTuple));
testTuple = Util.buildTuple(null, null);
assertNull(lastIndexOf.exec(testTuple));
testTuple = Util.buildTuple("xyzyy", "y");
assertEquals( ((Integer) "xyzyy".lastIndexOf("y")), lastIndexOf.exec(testTuple));
testTuple = Util.buildTuple("xyz", "abc");