CA resident here: YES, a written test is required. If you move in from another state, the written test is required anyway (I had to take it when I moved here!). They don't call this the Nanny State for nothing!!! And yes, make an appointment, or you'll be standing in line for hours and hours. The behind-the-wheel tests are definitely by-appointment-only and you have to either have taken and passed the written test, or get the waiver.
If the vehicle gets to a certain age (10 years, we think), the vehicle will probably be required to go to a certain type of smog station for its test. Even if it was just smogged a month before, the smog is required to be done right after purchase.
Don't try to buy a vehicle in one state and then register it in California. THAT is a headache. I know, we just did that when we inherited a vehicle outside of CA and brought it here. What a pain in the tush!