Should I write unit test for everything?

Question

I am wondering should I write unit test for everything. There are some classes is very difficult to write unit test. For example, I am writing some program for handling audi

Answer 1

I tend to write tests as much as I can. Not only to prove that something works, but to make it obvious to someone else when they inevitably break it later.

I've had a method that was 1 line long. In similar places in my app I had written unit tests, but being in a rush I thought that it could not possibly fail. I was wrong, it didn't work :-)

The additional benefit of writing unit tests is not only to test your code, but so that someone who has never seen your code before can read the tests and understand how your code should work given specific scenarios...like a specification.