Data warehouse or ETL testing or Web Services Testing can be categorized into four different sub categories irrespective of technology or ETL tools used in it. The four categories are listed below in detailed.
New Data Warehouse Testing : New DW is built and verified from scratch. Data input is taken from customer requirements and different data sources and new data warehouse is build and verified with the help of ETL Testing training tools.
Migration Testing : In this type of project customer will have an existing DW and ETL performing the job but they are looking to bag new tool in order to improve efficiency.
Change Request : In this type of project new data is added from different sources to an existing DW. Also, there might be a condition where customer needs to change their existing business rule or they might integrate the new rule.
Report Testing : Report are the end result of any Data Warehouse and the basic propose for which DW is build. Report must be tested by validating layout, data in the report and calculation.
Please add more on expansions of the said categories.