I am looking for a sample test with answers for Animal Farm to cover the novel, the 1917 Russian Revolution, and the Preface.
Are you a teacher or a student? If you are a teacher, one of the best things you can do instead of coming up with a test yourself is to actually divide your students into groups and get them to devise a test for each other that they then give to the other groups in your class. This helps students become far more familiar with a section of a novel themselves than if they were just going to be tested upon it and is also a great fun activity. I have done it myself a number of times and it really works!
If you are a student, you might like to think about doing it in a group with other students so as to help each other out. Sharing the burden like this makes the job more fun, quicker, and also improves your own knowledge of the section of the novel you are focusing on.
However, I have included two links below that should help you out. Enotes not only provides this question and answer service, but also gives a number of resources for a wide range of novels, that include tests on specific sections of the novel. Hope this helps!