r82386 added support for testing form validation message bubbles in DumpRenderTree on Mac. We need to add this support to WebKitTestRunner, too.
The lack of this support is causing a test to fail on the SnowLeopard WK2 bot: http://build.webkit.org/results/SnowLeopard%20Intel%20Release%20(WebKit2%20Tests)/r82439%20(10191)/fast/forms/validation-message-appearance-pretty-diff.html
I'll add the test to the Skipped file shortly.
Added to the mac-wk2 Skipped file in r82444.
These tests run fine for me on Mountain Lion WK2 Debug. This was probably fixed in http://trac.webkit.org/changeset/128030 for https://bugs.webkit.org/show_bug.cgi?id=95936
*** This bug has been marked as a duplicate of bug 95936 ***
Unskipped in http://trac.webkit.org/changeset/148693