How to write of create unit and integration test cases for testing SSIS

I am a SQL BI Developer, I have recently got a new job which a developer come tester role where I need to develop the SSIS packages and also implement the Automation testing on these packages. What should be the tools I can use to implement the automation testing in SSIS. I have did my research on this, I found some tools such as SSIS Tester Template and SSISUnit etc, but I do not have any exact documentation or web links which can give more clarity on how to create the test cases and do automation testing on SSIS packages. Can anyone help me in this?