This patch adds test cases for both checking amountoutstanding values
are handled correctly and also that the paid down accruing fines do not
add additional fines on increment.
Test plan:
Read the changeset and asses whether the changes/additional tests are
correct as per the expected behaviour.
Signed-off-by: Nick Clemens <nick@bywatersolutions.com> Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org> Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com> Signed-off-by: Joy Nelson <joy@bywatersolutions.com>