On 7/25/19 12:43 AM, Cyril Champier wrote:
*Adrian*:
If order is not an issue in the production code why test for it in the
test code?
In many cases, it would not be a problem in tests if we had an unordered
array comparison helper.
But in other cases, it is a production issue.
In ruby ActiveRecord for exemple, you can do `Patient.find_by(last_name:
'champier')`,
which translates to `SELECT "patients".* FROM "patients" WHERE
"patients"."last_name" = 'champier' LIMIT 1`.
If last_name is not unique, the returned record will be random.
Are you really looking for a pseudo-random name?
If so would not(warning not a Ruby developer, so below is tentative):
Patient.where(["last_name = :last_name", {last_name:
"champier"}]).order('RANDOM()').first
work better?
If not why not use something that returns all possible matches?
So yes, everything as to be randomized, because the sources are
multiples and the consequences can vary to a dramatic production bug, a
failed CI 1% of the time, or to a useless test assertion.
One way I can think of doing this is write a script that walks through
your tables in the test db and does an UPDATE across the rows. It is
going to add time to your tests, but then I believe that is going to be
the case for anything you do. Or you could look at something I have
never tried, fuzzy testing. As a starting point:
https://www.guru99.com/fuzz-testing.html
Maybe other folks have suggestions on tools you could use for fuzzy
testing.
*Peter*:
It might be an interesting exercise to implement this as a post-parsing
hook.
I known nothing about that, but that sounds interesting, do you have any
documentation pointer to help me implement that?
On Wed, Jul 24, 2019 at 10:36 PM Peter Eisentraut
<peter.eisentraut@xxxxxxxxxxxxxxx
<mailto:peter.eisentraut@xxxxxxxxxxxxxxx>> wrote:
On 2019-07-23 17:43, Cyril Champier wrote:
> In this documentation
> <https://www.postgresql.org/docs/9.1/queries-order.html>, it is said:
>
> If sorting is not chosen, the rows will be returned in an
> unspecified order. The actual order in that case will depend
on the
> scan and join plan types and the order on disk, but it must
not be
> relied on.
>
>
> I would like to know if there is any way to change that to have a
"real"
> random behaviour.
It might be an interesting exercise to implement this as a post-parsing
hook.
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
--
Adrian Klaver
adrian.klaver@xxxxxxxxxxx
