'With just a value for its C{last} argument,
L{ServerProtocol.setScrollRegion} writes a control sequence with
a parameter separator, that parameter, and finally a C{b\'r\'}.'

def test_setScrollRegionJustLast(self):

    self.protocol.setScrollRegion(last=1)
    self.assertEqual(self.transport.value(), ((self.CSI + ';1') + 'r'))
