def persons = new XmlSlurper().parseText(xml)
def firstnames = persons.person.firstname
assert firstnames.collect {it.text()} == ['Eddard','Tyrion', 'Robb', 'Daenerys']

def lastnames = persons.person.lastname
assert lastnames.collect {it.text()} == ['Stark', 'Lannister', 'Stark', 'Targaryen']

assert persons.'*'.find{it.@id.toInteger() == 3}.firstname == 'Robb'