'Dump_event cannot be tested directly without changing
environment variables. So, test statements in dump_event
indirectly'

def test_dump_event(self):

    text = self.text
    d = self.delegator
    text.insert('insert', 'foo')
    text.insert('insert', 'bar')
    text.delete('1.2', '1.4')
    self.assertTupleEqual((d.pointer, d.can_merge), (3, True))
    text.event_generate('<<undo>>')
    self.assertTupleEqual((d.pointer, d.can_merge), (2, False))
