From: Tom Lane <tgl@sss.pgh.pa.us>
To: Fabien COELHO <coelho@cri.ensmp.fr>
cc: David Fetter <david@fetter.org>,
 Arthur Zakirov <a.zakirov@postgrespro.ru>,
        Corey Huinker <corey.huinker@gmail.com>,
        PostgreSQL Development <pgsql-hackers@postgresql.org>
Subject: Re: [PATCH v4] Add \warn to psql
In-reply-to: <alpine.DEB.2.21.1907031618140.16913@lancre>
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 <alpine.DEB.2.21.1907031618140.16913@lancre>
Comments: In-reply-to Fabien COELHO <coelho@cri.ensmp.fr>
	message dated "Wed, 03 Jul 2019 16:29:23 +0200"
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Date: Fri, 05 Jul 2019 12:48:10 -0400
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Fabien COELHO <coelho@cri.ensmp.fr> writes:
> I agree that using TAP test if another simpler option is available is not 
> a good move.

> However, in the current state, as soon as there is some variation a test 
> is removed and coverage is lost, but they could be kept if the check could 
> be against a regexp.

I'm fairly suspicious of using TAP tests just to get a regexp match.
The thing I don't like about TAP tests for this is that they won't
notice if the test case prints extra stuff beyond what you were
expecting --- at least, not without care that I don't think we usually
take.

I've thought for some time that we should steal an idea from MySQL
and extend pg_regress so that individual lines of an expected-file
could have regexp match patterns rather than being just exact matches.
I'm not really sure how to do that without reimplementing diff(1)
for ourselves :-(, but that would be a very large step forward if
we could find a reasonable implementation.

Anyway, my opinion about having TAP test(s) for psql remains that
it'll be a good idea as soon as somebody submits a test that adds
a meaningful amount of code coverage that way (and the coverage
can't be gotten more simply).  But we don't need a patch that is
just trying to get the camel's nose under the tent.

			regards, tom lane