The ETL process is used for easy storage and management of data in the repository. This talk highlights and describes the characteristics of such processes testing. Particular attention is focused on how to create a working checklist for testing each class of tasks. The talk also describes the algorithms, how you can understand the problem if you do not have a technical specification at hand, which would describe the operation of the process. This talk can be a practical guide to action for the tester, who is tasked with verifying of the task associated with the data warehouse.