def METHOD_NAME(self):
    previous = self.auto_expand.getprevword
    expand = self.auto_expand.expand_word_event
    equal = self.assertEqual
    self.text.insert('insert', 'ab ac bx ad ab a')
    equal(self.auto_expand.getwords(), ['ab', 'ad', 'ac', 'a'])
    expand('event')
    equal(previous(), 'ab')
    expand('event')
    equal(previous(), 'ad')
    expand('event')
    equal(previous(), 'ac')
    expand('event')
    equal(previous(), 'a')