'Ensure overwrites existing notification with same id.'

def test_create_notification_id(self):

    assert (len(self.hass.states.entity_ids(pn.DOMAIN)) == 0)
    pn.create(self.hass, 'test', notification_id='Beer    2')
    self.hass.block_till_done()
    assert (len(self.hass.states.entity_ids()) == 1)
    state = self.hass.states.get('persistent_notification.beer_2')
    assert (state.state == 'test')
    pn.create(self.hass, 'test    2', notification_id='Beer    2')
    self.hass.block_till_done()
    assert (len(self.hass.states.entity_ids()) == 1)
    state = self.hass.states.get('persistent_notification.beer_2')
    assert (state.state == 'test    2')
