I've tested in Chrome, do I need to test in Safari?
Yes, but only for your fonts and JavaScripts.
I have noticed some of the default fonts are smaller on Safari then Chrome, also Chrome uses the V8 JavaScript engine which has caused some people problems, especially if you have a lot of form logic.
yes.
Oh, you wanted more detail? Simply, Chrome and Safari have a lot of different features in their implementations, and Safari is pretty widely used. If you expect the general public, and particularly those of us who work on Macs, to use your application, it would behoove you to test in the Safari browser.
In a word, No. You can't assume that because it works in one it will definitely work in all cases in the other. Sure, 99% of the time, it might be the same - but 99% isn't 100% - at least, it wasn't last time I checked. Call me a pedantic git if you like.
I've noticed Safari handles Asian characters better than Chrome. Also Chrome and Safari rely on the same Webkit for rendering pages, but their Javascript engines are totally different, so if you use Javascript in your pages you need to check both.
Yes, safari and chrome even though they are using webkit the two versions of webkit that are being used are significantly different. So you need to restest.
Safari uses 'mac' fonts, but Chrome would use 'Windows' fonts. I've noticed that there can sometimes be problems where using a font like Arial, it shows up fine in firefox/chrome/ie, but on Safari, it can cause a line to wrap because the font is slightly bigger.
Browsershots will send you screen shots of your page in just about every browser ever made.