IBM Mainframe Forum

I would appreciate any general suggestions on how to 'Negative Test' a mainframe application.
The type of application i'm testing is an ACH (All Clearing House) application called PEP+ by CheckFree.

I figure a negative test can result from either 'user error' fat fingering account numbers/amounts in a 'payroll' transaction
for example, or a system failure such as output data from the ACH application getting lost due to an intermediary application, such as an application that routes an ACH transaction to the deposits application being down.

Thanks

Hello and welcome to the forum,

Every piece of data that arrives as new input must be validated. A proper negative test will include multiple conditions for every field that is input (cannot be blank, must be numeric, must be larger than, must be less than, must be only certain values, etc, etc). What negatives that are tested depend on the business rules for that set of data.

Environmental issues should also be tested - things like you mention (data not sent), database system down or some other database error, error opening/reading data etc.

Hello Dick

Thanks, This is very informative.

currently we mock the production data in dev environment. For testing interfaces, would you suggest considering mocking the test data file for negative testing?

Thanks
Raj

Hello,

Either a subset of production (or a full volume copy if needed/desired) or the existing "test data" with all of the negative conditions incorporated could be used.

If there are performance considerations, full volume will give an earlier indicaton of any individual process problems.