'L{IMAP4Client.fetchUID} sends the I{FETCH UID} command and returns a
L{Deferred} which fires with a C{dict} mapping message sequence numbers
to C{dict}s mapping C{\'UID\'} to that message\'s I{UID} in the server\'s
response.'

def test_fetchUID(self):

    d = self.client.fetchUID('1:7')
    self.assertEqual(self.transport.value(), '0001    FETCH    1:7    (UID)\r\n')
    self.client.lineReceived('*    2    FETCH    (UID    22)')
    self.client.lineReceived('*    3    FETCH    (UID    23)')
    self.client.lineReceived('*    4    FETCH    (UID    24)')
    self.client.lineReceived('*    5    FETCH    (UID    25)')
    self.client.lineReceived('0001    OK    FETCH    completed')
    self.assertEqual(self._extractDeferredResult(d), {2: {'UID': '22'}, 3: {'UID': '23'}, 4: {'UID': '24'}, 5: {'UID': '25'}})
