def xmlString = """<GenerateOrResetPasswordFault>
    <faultCode>456</faultCode>
   <faultCode>123</faultCode>
</GenerateOrResetPasswordFault>"""

def expectedCodes = [123, 456]
def actualCodes = []
if (xmlString.contains('faultCode')) {
  actualCodes = new XmlSlurper().parseText(xmlString).'**'.findAll {it.name() == 'faultCode' }*.text() as Integer[]
  println "Actual fault codes are : ${actualCodes}"
  assert expectedCodes.sort() == actualCodes.sort()
} else {
  println "Response does not contain faultCode elements"
}