Re: [Quickfix-developers] Quickfix acceptance tests.

[Joerg T. <Joe...@ma...>]

Hi Tim,

thanks for the tests already provided. I did some initial reading 
whether the message should be ignored or rejected, but did not come to 
any conclusion yet.

> The automated acceptance tests for quickfix are impressive but have some
> very significant holes.
> 
> For example, the tests surrounding processing of resend requests do not
> cover the most common resend scenario, namely loss of synchronization after
> an unexpected loss of the TCP connection.   All the acceptance tests assume
> that sequence numbers are set to 1 at every logon.  However, it is usually
> at logon that the missing messages are detected.

Agreed. Since we use QuickFIX  in production, we see oft such kind of 
re-syncs. Probably I could grab some tests from production issues. But 
this kind of stuff is always difficult to analyse.

> One shouldn't, therefore, shouldn't get too complacent about the robustness
> of the quickfix session level code, especially when it is talking to a buggy
> peer fix app (e.g. one that often crashes), or over an unreliable network
> connection.

Actually, it is difficult to simulate an unreliable network connection. 
There are TCP/IP level tools to simulate that (nistnet), but I did not 
do any experiments so far. Perhaps it is possible to implement a "lossy"
low level socket read/write interface to be plugged in.

Cheers, Jörg

-- 
Joerg Thoennes
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