Bug 16423: (followup) Add more tests

Bug 16423: (followup) Add more tests

On fixing this tests, we retrieved the JSON data for the datatable used on
the 'Manage staged records' page. It would be cool to check the data it
carries makes sense.

To test:
- Run t/db_dependent/www/batch.t
=> SUCCESS: Tests pass
- Sign off :-D

Signed-off-by: Bernardo Gonzalez Kriegel <bgkriegel@gmail.com>
All test pass
prove t/db_dependent/www/batch.t
t/db_dependent/www/batch.t .. ok
All tests successful.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>