I live in constant worry of changing css and totally screwing up a completely unrelated bit of the web app
I understand this worry, but it makes me think that it may be a design problem with the CSS. Unrelated bits shouldn't be using the same CSS, related bits should probably change together.
In a more practical note, I have created selenium tests which capture screenshots and then saved those screenshots as artifacts in the CI (TeamCity) system. Having a human look at a bunch of static images makes for a faster and less error-prone sanity test to see if things are totally broken.
I agree it may be a design problem with the CSS, I agree.
But my point is exactly that: I can't just go in and _improve the code_ (extracting classes, rewriting it in less/sass or whatever) because to verify the changes do not mess up the UI requires clicking around many pages in half a dozen browsers in three OSes.
And thank you very much for the practical note, it's an interesting idea!
One other practical note, you can create a single (test) page that showcases all of the visual styles currently in use, so there is one page to check manually.
I understand this worry, but it makes me think that it may be a design problem with the CSS. Unrelated bits shouldn't be using the same CSS, related bits should probably change together.
In a more practical note, I have created selenium tests which capture screenshots and then saved those screenshots as artifacts in the CI (TeamCity) system. Having a human look at a bunch of static images makes for a faster and less error-prone sanity test to see if things are totally broken.