At my experience level, I'd want to test ride first. It may be through a friend who has the same bike in the same size, but I'd need a test ride first. I wouldn't go to an LBS to test ride, then go buy online though. To me that would be unfair.

I live in an area that has many bike stores to choose from. While hunting for a bike, I visited several and the experience ran the gambit of super helpful to utter snobbery.
If my only LBS was as clique-ish and as stuck up as one particular store I visited, I would buy online in a heart beat. I can't support an LBS who makes a newbie feel so out of place and I would certainly go through the struggle of shipping bikes back and forth until I found the right one just to avoid an LBS like that.

Luckily they aren't the only LBS in my area and I found a good one.