I asked earlier whether Ajahn Chah said more on the nature of stream-entry. I did find this story, retold by Ajahn Amaro.
"The newcomer proudly introduced himself as a stream-enterer (the first stage of Enlightenment in which one is free from the first three of the 10 fetters that bind one to the sensuous world). After replying “In the village I’m from, stream-enterer is another word for a mangy dog,” Ajahn Chah watched the new arrival stomp off in anger. “Well, so much for stream-entry,” he commented in so many words."http://www.abhayagiri.org/main/article/1878/
My interpretation is that Ajahn Chah was testing the newcomer. And the test seemed to concern whether this person had really gotten past identity-view or not. If this person had, I suspect there would not have been the stomping off in anger. So Ajahn Chah concluded - nope. (I'm sure Ajahn Chah would have tried to help this person more if they had stuck around, but pride seems to have been more important than being open enough to hear what a teacher was saying. Too bad!)
The rest of that article is quite relevant to the question “How do you know when you are enlightened?”
"When one thing is practiced & pursued, ignorance is abandoned, clear knowing arises, the conceit 'I am' is abandoned, latent tendencies are uprooted, fetters are abandoned. Which one thing? Mindfulness immersed in the body." -AN 1.230