searching for UNSEEN emails is returning empty list

[ermamud]

To Reproduce

    ImapClient client = new ImapClient();
    await client.connect("imap.mail.yahoo.com", 993, true);
    await client.authenticate(new ImapPlainAuth("******", "*****"));
    ImapFolder inbox = await client.getFolder("inbox");
    List<int> emails = await inbox.search('UNSEEN');

in this case the emails list has 1 positon with null value.

Expected behavior
Search should return the email ID list

[michaelspiss]

I was able to reproduce with the following log

[INFO] imap_client: S: * 1 EXISTS
* 0 RECENT
* FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
* OK [PERMANENTFLAGS (\Answered \Flagged \Draft \Deleted \Seen \*)] Unlimited
* OK [UNSEEN 1] Message 1 is first unseen
* OK [UIDNEXT 148] Predicted next UID
* OK [UIDVALIDITY 1513286925] UIDs valid
A4 OK [READ-WRITE] SELECT completed

[INFO] imap_client: C: A5 UID SEARCH UNSEEN

[INFO] imap_client: S: * SEARCH 147
A5 OK UID SEARCH completed

[null]

Seems like the catching doesn't work - I'll have to look into it as soon as my schedule allows