Kindly go through this document.
How do I do a test with full IPN data? At the moment a test just sends a blank IPN request to my IPN url.
Kindly set up a product on PayDotCom and make it $1, after that please purchase the product which will send IPN call you are looking for. You can make an account here:
You can also use the IPN Simulator under your "More Settings==>My Account" section.