Using protractor to test link colours

How does one test the colour of the link on hover using protractor?

I want to simulate the mouse hovering over a link, that link changes from say white to blue and then I want the test to expect that the colour = blue, on hover. I have literally searched the entire web and cannot find any answers to this problem. Also I realize this is a slightly different question but what else is good to test on a page? I have tested that when a link is clicked that the current URL is equal to what I expect but I am struggling to think of other ideas and would be good to find a site which has a list of all possible tests (again, I cant find anywhere like this after searching high and wide. I have been on the main protractor page and it is a good start but doesn't include lots of possible tests, only a few)