Nasty fatal if you try to create a contribution via the api with an invoice id matching an existing

This would be a NICE one for someone @ the sprint writing their first UNIT TEST

Fix is to alter the _civicrm_api3_basic_create to deal with the possibilty of a CRM_Core_Error having been returned - something like this but this is not giving the actual error message.

This can be reproduced in a test by creating the same contribution twice in a row with the same invoice id.

In the longer term we should through exceptions rather than returning an error in the BAO

if (is_null($bao))

{ return civicrm_api3_create_error('Entity not created (' . $fct_name . ')'); }

elseif (is_a($bao, 'CRM_Core_Error'))

{ throw new API_Exception($bao->getMessages()); }