Considering the increasing complexity of DW/BI systems and their lengthy implementation cycles, testing often tends to be undermined. But testing of DW/BI system is vital to ensure information accuracy, reporting efficiency and data security, among others. The quality of a BI system is only as good as the quality of its underlying data. Inconsistent coding, duplicate entries, missing data values, and failure to integrate data from multiple applications are some of the frequently reported issues that make Data Warehouse/ETL testing a necessity. Moreover, ETL systems constantly evolve because of alterations in the source systems and business rules, changes in business requirements, and constantly expanding data.
While organization cannot afford to implement a DW/BI system without testing, DW/BI testing is often a challenging proposition as it requires specialized skills, tools and approaches.