'Evaluate cancelling with CTRL-\.'

def test_ControlBackslash(self):

    self._testwrite('cancelled    line')
    partialLine = self.recvlineClient.expect('cancelled    line')
    def gotPartialLine(ign):
        self._assertBuffer(['>>>    cancelled    line'])
        self._testwrite(manhole.CTRL_BACKSLASH)
        d = self.recvlineClient.onDisconnection
        return self.assertFailure(d, error.ConnectionDone)
    def gotClearedLine(ign):
        self._assertBuffer([''])
    return partialLine.addCallback(gotPartialLine).addCallback(gotClearedLine)
