It depends on the location of the driving test and the tester. Most testers require you to parallel park, however if you are in a rural area where parallel parking is not the norm, you may not have to.
Call the testing location and they will tell you if their tester requires parallel parking, if they won't tell you, assume that they do.
All written driving tests are hard. Study the driving manual closely, especially the raod signs. If you pass all of the written questions, just not being able to parallel park generally does not fail your entire test.
Good Luck.