Bug 10710: add unit tests for OfflineOperation's routines in C4/Circulation.pm

Bug 10710: add unit tests for OfflineOperation's routines in C4/Circulation.pm

This patch test AddOfflineOperation,GetOfflineOperation and
DeleteOfflineOperation in C4/Circulation.pm.

The tests are wrapped in a transaction.

Note: Currently, GetOfflineOperations is not tested because we cannot
mock C4::Context->userenv in unit tests

To test:

prove t/db_dependent/Circulation_OfflineOperation.t
t/db_dependent/Circulation_OfflineOperation.t .. ok
All tests successful.
Files=1, Tests=7, 19 wallclock secs ( 0.01 usr  0.01 sys +  0.33 cusr  0.02 csys =  0.37 CPU

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>