Can I test drive and/or buy a vehicle with only a permit?

I am looking to buy a Eurovan. I found one online that looks like it’s in really good condition and is in my price range. The problem is, I won’t have my license for a few more weeks, and would really like to go test drive it. If I took someone with me that had a license, would I be able to test drive it? What about buying it? I know I couldn’t buy it on my own without a license, but If I had a cosigner would that be possible? This is in California, by the way.