`min(1%, 2%, 3%)` should stay `min(1%, 2%, 3%)` instead of collapsing to `calc(1%)`, given we can't conclude whether 1% is positive or negative. Same for `max(1%, 2%, 3%)`.
<rdar://problem/111986644>
The only exception to this is if there's only one argument (see bug 259037)
So arguably, WebKit's behavior is more correct here, since it does the collapsing only for properties that have a non-negative range. The test should perhaps be adjusted to test for both types of properties.
It does look like the test uses text-indent, which does take a negative range as well, so WebKit isn't working as intended here.
Hmm, this is more about whether a percentage can resolve to a negative value. `text-indent` / `margin-left` percentages are relative to the size of the containing block...