One problem with hexdigest is that it's longer and the column was
created as binary(16). We don't have a mechanism to run migrations on
this table, so we use UNHEX in SQL to have the equivalent as digest()
from hexdigest()
Co-authored-by: Jérome Perrin <jerome@nexedi.com>

Jérome: slightly adjusted manually to just use range where it does not
make a significant difference (for example in test)

also str representation of unicode character is different.

Co-authored-by: Carlos Ramos Carreño <carlos.ramos@nexedi.com>
Co-authored-by: Emmeline Vouriot <emmeline.vouriot@nexedi.com>
Co-authored-by: Kazuhiko SHIOZAKI <kazuhiko@nexedi.com>

This reverts 8a5f5b5b (ZMySQLDA: fix string_literal usage, 2023-03-14)
to apply this logic one step lower, because CMFActivity uses
db.string_literal directly.

this works with astroid 3.2.0 and pylint 3.2.0

on python2, we use have a [python patch][patch] to globally make
asyncore use poll, at that time we were using medusa and it was not
exposing an option to use something else than select.

[patch]: https://lab.nexedi.com/nexedi/slapos/-/blob/180f1553fa7774f05ae8e739dfef43fa2ae56c0a/component/python-2.7/asyncore_poll_insteadof_select.patch

also add the missing tests