The file at LayoutTests/fast/dom/HTMLImageElement/image-src-absolute-url.html changes the base URL and is supposed to check that the src URL changed to reflect that. Instead it checks against the old base URL seemingly in error, and furthermore, the url is not updated as would be expected. The two problems cancel each other out, which is why the test passes.
Specifically, the first of the two "after" lines currently reads:
SUCCESS (document.images.src = file:///does/not/exist/test.jpg)
I believe it should read:
FAILURE (document.images.src = file:///also/does/not/exist/test.jpg)
The reason that this is failing will need to be identified and fixed and the layout test updated.
This test verifies that the behavior matches WinIE - is there a reason why it should be different?