Verifying if all the data has been scraped

[Billy John]

My spider has scraped 72 000 items. According to my calculations there should be 74 000 items. There are no errors in the log. How do i check if all items are scraped and which item is not?

Can i make a contract to be checked against each and every request and print some log message with page number where contract is not met? How can i do that?