what does this mean (ex bf's reply on twitter)?

[Reagan Roulette]

I tweeted: I am a good person with a good soul and I am skinny with an excellent rack. try to top that

My ex bf commented on this on Twitter: i have a fat tester for that.

I dont know what a fat tester is and I cant tell if hes kidding or being mean. He has told me a million times Im attractive with an excellent rack but was very nasty and mean to me when he dumped me. and no my twitter is private and my tweet was in response to something someone else said

[knightrunner13]

Doe's it matter he is your ex and an assh@le who cares what he thinks ?. If he was any kind of a good man you would still be with him !