'read_*_eager()
Read all data available already queued or on the socket,
without blocking.'

def _read_eager(self, func_name):

    want = ('x' * 100)
    telnet = test_telnet([want])
    func = getattr(telnet, func_name)
    telnet.sock.block = True
    self.assertEqual('', func())
    telnet.sock.block = False
    data = ''
    while True:
        try:
            data += func()
        except EOFError:
            break
    self.assertEqual(data, want)
