Unit Testing

[pianoperformer]

Hi,

Does anyone know of a good unit testing framework for C#? I'm trying to get more into the agile development mindset, even though I work by myself, and want to do unit testing.

[JimOfferman]

www.csunit.org (first result in Google, if you type in C# unit testing)

Note that unit testing is not the Holy Grail of software development and doesn't make you more agile per se.

[pianoperformer]

Yeah I know I could have searched, but wanted to know what people have used and liked.

Hmm, isn't unit testing usually one of the core ideas of agile development?

Thanks for the link.

[SomebodySomewhere]

You could also use NUnit. If you have Visual Studio 2008 Professional then you could use the built in unit testing capability for .NET !

[Trezker]

NUnit is good.

Unit testing is not be the holy grail, nothing is. But it's a damn good tool that lets you be 100% sure of what parts of your code is working and exactly when it breaks.

Simply put, Unit testing is good for heart, soul and a good nights sleep.

[pianoperformer]

Oh, Visual Studio 2008 has unit testing? And I was thinking I wasn't going to need to upgrade. *sees wallet emptying*

Oh yes, I remember nUnit. I used it a while back I think.

I already know that unit testing is useful. I used it a while back in C# but couldn't remember what I used, and I used it in PHP quite a bit.

[JimOfferman]

Unit testing is a tool for agile development, not the tool.

The problem with unit testing is that when all your tests succeed, you still don't really know if the program as whole functions as it should. Also, you can't really unit test a complex user interface or anything that has emergent behavior (such as the games I work on).

I prefer a "design by a contract" approach, where you define and check the pre- and post-conditions of any interface method, as well as the invariants.

[pianoperformer]

Jim,

If the individual parts work, then the entire thing should work together, if you have really come up with enough tests.

This is why you use functional testing for the entire program (including the user interface). Have you ever used Selenium? I've had limited experience with it but it looks very useful for exactly that.

[JimOfferman]

Originally Posted by pianoperformer

If the individual parts work, then the entire thing should work together, if you have really come up with enough tests.

Yes, in theory unit testing is great. But the problem is that the theory doesn't always work out in practice.

1. It may not be possible or practical to come up with enough tests.
2. Unit tests only work within the scope of a wholly controlled environment, which excludes all major OS-es.

This is why you use functional testing for the entire program (including the user interface). Have you ever used Selenium? I've had limited experience with it but it looks very useful for exactly that.

Never heard of it. Quite frankly, I have little incentive to investigate testing methods, because we have a big QA department at work (the little programming I do at home doesn't warrant anything beyond the most basic 'does it work?' testing). We catch most of our bugs by doing peer reviews, btw.

[pianoperformer]

Jim,

If you use TDD (test-driven development), you write your tests before your code, and are really only supposed to write the code to fulfill exactly those tests. If there is something new it needs to do, you first write a test, then write code until it passes. Well that's how it goes in XP, anyway.

Not sure what you mean about the OS. Hopefully the development environment should be fairly similar to the production environment.

[JimOfferman]

I'm familiar with TDD and XP. Again, there are limits to what you can write tests for. I work in real-time graphics... you can't write units tests for a lot of the things I do on a daily basis. You can't write a test that tells you if the shadows look good.

By OS I meant the Operating System. You know, Windows and all

You can never have a system complex as your garden variety multi-tasking, multi-processor OS in the exact same state twice; that only works in theory. This makes it hard to fully unit test complex applications that are designed to run in such an environment.

[pianoperformer]

True. But I guess it depends on what the program does. I certainly wouldn't use it for graphics.

I mostly make web sites, so my experience with it is limited to that domain, which it works quite well for.

[Trezker]

I heard behaviour driven development is a better way to think of unit testing.

Beyond Test Driven Development: Behaviour Driven Development

[pianoperformer]

Weird, I've never heard of that. I'm not sure if I agree yet, but it sounds interesting. I just looked it up on wikipedia real quick. I'll listen to the video later.

The outside in sounds like a top-down approach, which I tend to agree with.

Anyway, thanks for the link.

[igmistro]

Originally Posted by pianoperformer

Oh, Visual Studio 2008 has unit testing? And I was thinking I wasn't going to need to upgrade. *sees wallet emptying*

Oh yes, I remember nUnit. I used it a while back I think.

I've been using VS2008 since last December. Built in unit tests are nice but you don't need to upgrade if that's all you want. Since you've used nUnit before I'd go back to that...