I've never seen signs that said "Survive the test". We do encourage students to eat a good breakfast & get plenty of sleep the night before.
The students at the school where I teach have 2 kinds of standardized tests: the state graduation tests, and state-developed & graded end-of-course-tests. If they don't pass the former, they don't get a diploma (with certain limited exceptions). By law in our state, the latter are counted as 15% of the semester grade. So, for both tests, it's in the student's interest to do well.
Since NCLB, our school is graded on student performance on the tests and also on how many students are present for the test (apparently some schools used to encourage lower-performing students to stay home on test day to make their average scores higher).
Now that is an interesting guess. Can't say it is wrong. I just had not made that connection. Sure would be nice if that is what is was. Otherwise to me it sounds, well, less than inspiring.
The pictures are recent. The posters are hanging on the cafeteria wall as I write this.