Do you write your unit tests before or after coding a piece of functionality? [closed]

Answer 1

I follow a TDD approach, but I'm not as much of a purist as some. Typically, I will rough in the class/method with a stub that simply throws a NotImplementedException. Then I will start writing the test(s). One feature at a time, one test at a time. Frequently, I'll find that I've missed a test -- perhaps when writing other tests or when I find a bug -- then I'll go back and write a test (and the bug fix, if necessary).

Using TDD helps keep your code in line with YAGNI (you aren't gonna need it) as long as you only write tests for features that you need to develop AND only write the simplest code that will satisfy your tests.

Answer 2

Normally I write unit tests before the code. They are very beneficial and writing them before the code just makes sense. Dependency injection lends itself well to unit testing. Dependency injection allows for parts of your code to be mocked out so you only test a particular unit i.e. your code is loosely coupled and it’s therefore easy to swap out for a different (in this case mocked) implementation.

Answer 3

I tend to use unit tests to test the code as I'm writing it. That way I'm using what I'm writing at the same time, as I use the unit test to test code while I'm writing it. Much like a console app would.

Sometimes I've even written tests without asserts, just debug outputs, just to test that how I use something is working without exceptions.

So my answer is, after a little bit of coding.

Answer 4

I usually write a list of the unit tests I will be writing before I write the code, and actually code the unit tests after, but that's because I use a program to generate the unit test stubs and then modify them to test the appropriate cases.

Answer 5

We try and write them before hand, but I will fully admit, that our environment is chaotic at times, and sometimes this step is initially passed over and written later.

Answer 6

I'll offer that I'm fairly new to writing unit tests, and that I wish I had written them before I wrote my code. Or, at least had a better understanding of how to write more testable code as well as a better understanding of concepts like dependency injection which seems to be critical to writing testable code.