Tests 001 to 004 are tests of CSS2, section 9.5, normative paragraph 6:

# A float can overlap other boxes in the normal flow (e.g., when a
# normal flow box next to a float has negative margins). When an
# inline box overlaps with a float, the content, background, and
# borders of the inline box are rendered in front of the float. When a
# block box overlaps, the background and borders of the block box are
# rendered behind the float and are only be visible where the box is
# transparent. The content of the block box is rendered in front of
# the float.
 -- http://www.w3.org/TR/REC-CSS2/visuren.html#floats


For some of these tests you will need Todd Fahrner's Ahem font, which
you can download from:

   http://www.hixie.ch/resources/fonts/

Versions for Mac, Unix and Windows are available.