Thanks for suggestion Ashutosh, I have done testing around these suggestion and found no issues. I will continue testing same with updated patch posted on this thread.
Here are some of the additional test-cases that I would suggest you to execute, if possible:
1) You may try running the test-cases that you have executed so far with SR setup and see if the changes are getting reflected on the standby.
2) You may also try running some concurrent test-cases for e.g. try running these functions with VACUUM or some other sql commands (preferable DML commands) in parallel.
3) See what happens when you pass some invalid tids (containing invalid block or offset number) to these functions. You may also try running these functions on the same tuple repeatedly and see the behaviour.
