This page has been floating around in links over the past couple of weeks, as a collection of test cases to compare e-mail address validating regular expressions. However, watch out: it’s wrong.
RFC822/2822 defines an email address with a bare IP address domain part as using:
domain-literal = [CFWS] "[" *([FWS] dcontent) [FWS] "]" [CFWS]
In other words, this test case is not valid at all:
Instead, it should be:
ditto for the other addrs using IP addresses in the domain part. They’re rare, but the non-bracketed form is definitely not legal and should not be considered so in the test cases.
I sent a mail to the author a few days ago without response, hence this post.