Thank you for the question, I don't fully understand exactly what the contents of the inbound and outbound file would be, but hopefully this helps.
Agile Requirements Designer can be used to model the expected behaviour of data transformations, although we don't have a full solution for this out of the box. We have an integration with CA TDM, which is able to connect to databases to extract data. The expected result of each ETL test case could be exported from ARD as a CSV dataset.
This would give you a set of ETL test case definitions which you could execute manually or automate in some way.
Thanks
Josh