please let me know how do i retrieve the deleted testcases
Hi and welcome to the Testiny forum!
See these forum post on how to undelete test cases, test runs should be the same just use testiny.testrun instead:
If you mean re-adding test cases to a test run that got removed from a test run, then just add the respective test cases again, all previous linked information (like comments, defects, …) will be there again, only the result will be reset.
Best regards,
Alex