ETL Testing Process:

Similar to any other testing that lies under Independent Verification and Validation, ETL also go through the same phase.

• Business and requirement understanding
• Validating
• Test Estimation
• Test planning based on the inputs from test estimation and business requirement
• Designing test cases and test scenarios from all the available inputs
• Once all the test cases are ready and are approved, testing team proceed to perform pre-execution check and test data preparation for testing
• Lastly execution is performed till exit criteria are met
• Upon successful completion summary report is prepared and closure process is done.

It is necessary to define test strategy which should be mutually accepted by stakeholders before starting actual testing. A well defined test strategy will make sure that correct approach has been followed meeting the testing aspiration. ETL testing might require writing SQL statements extensively by testing team or may be tailoring the SQL provided by development team. In any case testing team must be aware of the results they are trying to get using those SQL statements.