This is Not a Test is, in some ways, a traditional zombie tale. It pays homage to the Romero blueprint without explicitly wink-winking at it: a diverse group of people hole up in one location to protect themselves from a nasty case of the dead coming back to life, for reasons that aren't explained and don't matter. The twist is that the characters and location are Summers' speciality: psychologically tortured high school kids in a high school.
The main character, Sloane, is a particularly interesting one to throw in a story of survival, because she doesn't want to survive. She starts the book trying to kill herself. Somehow, it goes downhill from there.
This isn't really about zombies. They are only a catalyst for the even greater horror of dealing with people who still have heartbeats when they're put under enormous pressure. That pressure, coming from both the current situation and memories of the past, puts the characters through some horrible ordeals. The misery dripping off of every page is written so beautifully and honestly that it avoids being emo to the point of cheesiness. Still, it requires a certain sick desire to see characters suffer to enjoy a novel like this.
This is a test: do you like zombies? Do you like feeling terrible after reading about the intense social situations that zombies tend to elicit? If you answered "yes," you pass: go read This is Not a Test.