'When L{HistoricRecvLine} receives a keystroke for an unprintable
function key with no assigned behavior, the line buffer is unmodified.'

def test_unprintableCharacters(self):

    kR = (lambda ch: self.p.keystrokeReceived(ch, None))
    pt = self.pt
    for ch in (pt.F1, pt.F2, pt.F3, pt.F4, pt.F5, pt.F6, pt.F7, pt.F8, pt.F9, pt.F10, pt.F11, pt.F12, pt.PGUP, pt.PGDN):
        kR(ch)
        self.assertEqual(self.p.currentLineBuffer(), ('', ''))
