Bug 27593: Regression tests

Bug 27593: Regression tests

This patch introduces tests for the behaviour change (400 => 404) and
also adds tests for untested (error) behaviours. Notably, the 'Biblio
not found' problematic return value couldn't be triggered, because the
OpenAPI plugin returns a 500 because the response was malformed
(expected { error => 'message' } and it was returning a string).

For the above reason, running the regression tests will show a 500...
instead of the expected 400.

I covered the rest of the codepaths that trigger errors to have full
coverage.

To test:
1. Apply this patch
2. Run:
   $ kshell
  k$ prove t/db_dependent/api/v1/clubs_holds.t
=> FAIL: Tests fail loudly

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>