We examined the audit procedures for reviewing batch controls previously as part of the discussion of input controls. Testing run-to-run controls is a logical extension of these procedures and needs no further explanation.
Tests of transaction codes and sequence checks can be performed using ITF or the tests–data approach.
The auditor should create test data that contain records with incorrect transaction codes and records that are out of sequence in the batch and verify that each was handled correctly.
Implicit in this test is verifying the mathematical correctness of the computer operation.
For example, consider a sales order for five units of product valued at $100.
Assume that before the transaction is processed, the current value of the customer’s account is $1,000 and the inventory in question shows 250 units on hand.
After processing, this transaction should increase the customer balance to $1,100 and reduce the inventory to 245 units.