ETL testing in Business Intelligence (BI) Applications

Importance of Business Intelligence has never been more than today. Data, Big Data, Structured, Unstructured, BI reports, BI Analytics etc are heard so often today…
This blog is focused on testing aspects of ETL(Extract, Transform, Load) part of Business Intelligence (BI) Applications. Lets talk a bit about BI Application first to bring everyone on same page and then we will go into testing strategy. Typically BI Application means building a DataWarehouse, then some DataMarts and finally a Reporting layer which could be Self Service BI (Eg. Microsoft Power BI) or Canned reports (Eg SSRS) or Power Reports. There are several others less common ways like building a UI layer to present data or futuristic ways of building a Windows 8 App as reporting layer. Other important thing to understand about BI systems is they are ‘after the fact’ reporting systems. 

Testing ETLs have always been challenge, complicated and always keeping test managers on toes.
Below diagram depicts sequence of steps to be followed to test ETLs. This is purely around test execution part. Refer to this blog post to learn more about MiniDB concept.