If you don't have the CSS testing fonts installed, many tests will appear to fail! Install the CSS Testing Fonts if you want accurate test results.
The Ahem font is available in several formats for different systems. If we are missing yours, and you can create one, we would welcome your contribution. Send us a message on the public-css-testsuite mailing list.
/Library/Fonts(available for all users on the machine) or
~/Library/Fonts(available to current user only)
Some tests require additional fonts. A zipfile of all CSS testing fonts is available.