The purpose of this paper is to describe general data warehouse structure and background, as well as specific situations encountered during the testing effort for our project. Our project was to test a data warehouse and data mart for a large research department of a pharmaceutical manufacturing company. This was a pilot project and our efforts, if successful, would pave the way for future data warehouse projects within the company. Our role on the project team was to provide quality through validation of the business rules. We met this challenge by determining if the extract/transform/load (ETL) process was functioning in the approved manner. We created basic principles that were used as a starting block for our process.