I would suggest taking the time and putting in the effort of reading the actual book before trying to take an AP test. I would say that you will not get enough understanding of the book just from Spark Notes.
You are selling yourself short if you are looking to resources like SparkNotes in place of reading a book. Most of these sights give good basic (some in depth) information, but there is no way these sites can convey the tone, emotion, voice, dynamics of either the writing or the characters. So no, reading SparkNotes is not a sufficient substitute for reading the book.
These posts are offering you excellent advice. I strongly doubt that anyone could pass AP testing without reading the material, and I know from my experience teaching AP Literature that students who do not do the assigned reading achieve very little and frequently fail the course entirely, as well as failing the AP Exam at the end of the course. I would encourage you to not put yourself in this position. Don't take an AP language or AP literature class unless you are willing to make a commitment to reading and studying the assigned selections, both in class and as homework. AP is hard work! Good luck.
Not only that, but why on earth would you want to be in AP English if you don't want to read this book? I understand that some students want to do as many AP classes as possible in order to impress college entrance reviewers, but I think that if you do not like reading enough to read this book, you do not belong in AP English.
I would certainly not advise taking a pre-AP test for any work based on Spark Notes. Most honors and AP teachers are very familiar with Spark Notes and other such sites and base their tests on material that is not discussed in/on those books/sites.
Moreover, most pre-AP classes seek deeper understanding and analysis of works than Spark Notes offers. I would advise this--when students resort to using Spark Notes or other summaries instead of reading the actual works, it truly hurts their performance on tests and exams. It is okay to read the work and then use supplemental material like this site or others to see if you understand what you're reading. But, when a student relies solely on summaries, he/she loses the opportunity to hone critical reading skills that are vital to reading and analyzing the complex passages found on AP and SAT exams. Spark Notes removes any chance of students learning vocabulary through context or being able to model or personally analyze a writer's style.
I don't think it is appropriate to read anything other than the actual work. It deprives you of so much understanding of the world around you especially helping you to find out what the experience is like.