Why do Tests Matter soooo Much?

So here I am, end of week four, teaching a couple of classes now, and wondering why state tests are at such high stakes for students AND teachers. These past couple days, we have been reviewing random questions for the HSA (Hawaii State Assessment). Mostly questions from material we haven't covered yet, so if it is on their test, they might have an idea of how to solve, or answer it. They actually get three different chances to pass the test, and prove they are "smart enough" or they have "learned enough" to move onto the next grade level. I mean I can see some importance in doing so, but there is sooo much pressure on the teachers to make sure your students pass. As well as on the school to pass AYP. So are we math teachers here to teach students, and help them gain a wide understanding of mathematics, or are we here just to teach them material that they will see on the test? Because sometimes that is what it seems like! Teachers are just pushed to make sure their students do good on tests, but is that the only way to measure learning? Anyway.. just some thoughts...