When changing the content-div's font to something other than the default, the text in the first box crosstalks into the float's space, instead of being flown around it.
In the GTK port, With
The test passes: both in the current nightly build and back around when this bug was first reported (I used r129138 to test this). Without that, the test follows the behaviour stated in the description, and the text enters the float's space.
I will try to find the actual revision where this was fixed.
After bisecting a bit, I found that this was fixed by bug #101803 in r137331: <http://trac.webkit.org/changeset/137331>
I resolving it as FIXED, but feel free to reopen if you think I am mistaken.