Assert_select '[foo|=bar]' bug?

just for the record, i tried searching the archives on this one but
would get an application error when i tried entering |= in the search
field.

assert_select ‘[foo|=bar]’ behaviour does not seem to jive with the css
specs:

http://www.w3.org/TR/CSS21/selector.html#q1
http://www.w3.org/TR/css3-selectors/#selectors

is there some reason i don’t know about for this or is it a genuine bug?

_c