more testing

[aladdin-add]

The reason I originally wrote this plugin was I wanted to start using ESLint in a very large repo. There are too many linting errors been reported, some can be auto fixed, while some more rules don't support auto fixes. To avoid too much manual modification, I wrote an initial version, but there were some edge cases that I didn't consider, and not well tested.

Perhaps for similar reasons, some users are now using the plugin. we have got several bug reports (e.g. #55, #57). I think it's time to do something - more testing, and add a note in docs: do not use in production! :)