Aaron Sumner


Rails testing in the real world

I’ve been in the web development racket since the mid-90s, but I’m really not a programmer (even if I’ve held jobs that state otherwise). I know how to at least do many things expected of a programmer, but it’s not something I do at my job for more than, say, eight hours a week. There are just too many things to do. That said, I have been doing this for more than 15 years now, and I know a thing or two about how things should work. It took time and experience and learning the hard way at times, but these days I’m solidly convinced that if you’re not using–and embracing–a framework of some kind you’re making life more difficult than it has to be. And part of that embracing is writing tests for your code to pass.

Everyone knows test-driven development (TDD) is the way to go, right? Like all the other big player web frameworks, Rails has built-in support for tests (Test::Unit) and a bevy of third-party test frameworks (Rspec, Shoulda, Cucumber). TDD evangelists preach TDD as the way to go about your business. I’ve read their statements and worked through the tutorials, but whenever a new project came along, I’d start the same way as always: Draft a data model, write some code, check it out in my browser, and hope I didn’t miss anything.

I attribute this behavior to two things. First, I’d become set in my ways as a slapdash, spaghetti code developer; and second, the demos and tutorials intended to get you hooked on Rails–be it the 15-minute blog in Rails demonstration that got everyone excited in the first place or the book Agile Web Development in Rails that was the first hands-on exposure to Rails for many of us–testing is either not done or is an add-on. Even Ryan Bates’ essential Railscasts series omits testing unless the week’s topic is about a testing framework. I know why this is so–people don’t come to Railscasts to see Ryan write a bunch of tests and make them pass; they come to see him implement a useful controller feature or neat drag-and-drop interface. At the end of the day I got it, but I didn’t get it, and so I didn’t do it. A whole book on the subject of testing in Ruby, The RSpec Book, couldn’t convince me, but I knew I needed convincing, so I kept trying to find testing enlightenment.

Everything clicked for me after watching a few episodes of BDDCasts, an ongoing screencast series that gives you the opportunity to look over the shoulders of two seasoned, test-driven Rails developers as they put together an application, feature by feature. It’s not always pretty, but watching and listening to the two talk through implementation decisions, leading off with defining features through tests, helped me realize that the only way I was going to really put tests to use on my own was to make the process work for me–not the other way around.

Here’s the development process I’ve come up with for myself to test Rails code. Your mileage may vary.

  1. Create a new Rails app and prepare it for the testing frameworks of your choice. I’m currently using Cucumber, Webrat, and Pickle for behavior tests, RSpec to spec out and test the particulars of my models, and Factory Girl to create my test data. At this time I don’t do a whole lot of controller testing, as I’m still figuring how to work that into my system, but at this point Cucumber has kept things afloat on that end for me.
  2. Draft a data model. I know this is probably against many TDDers’ rules, but I need a general lay of the land before I get started. I do this on paper, with lines between tables to mark relationships.
  3. Begin writing feature files using Cucumber. I’ve been fuzzy on the preferred way of organizing behavior tests are–should I use a few files with several features each, or many files with a handful of features per? I’ve gone the latter route. This lets me focus on features in more manageable bundles, and also makes it easier for me to take advantage of Cucumber’s useful Background feature. I don’t know if this is the right way to do it, but it’s the way that works for me.
  4. Crank out the required scaffolds. Scaffolds? Aren’t those just for beginners? Maybe they are, but scaffolds do a lot of grunt work I’d prefer not to do. This might be my biggest veering-off point from what the demos and tutorials say you’re supposed to do. Instead of writing a test and then writing the code to make it pass, I write a test, create a scaffold using Bates’ awesome Nifty Generators gem, then peel back what I don’t need. At this point I create my factories, write the code need to write to make my Cucumber tests pass, remove the rest, and do a round of refactoring.
  5. Clean up my models. I use RSpec to verify that things like validations and after_create calls are working as intended. I could do this in Cucumber, but these tests make more sense to me within RSpec. Another important thing to note here is that I don’t test things that I can safely assume have been tested thoroughly by the Rails framework itself, such as ActiveRecord-specific calls, and ideally if a plugin or gem is well-tested I trust those tests as well. Another round of refactoring follows, as needed.
  6. Move on to the next bundle of features–it’s back to Cucumber, writing another set of related features, and making them pass.

That’s my process, in a nutshell. I don’t obsess over coverage statistics, but I still think by and large this process is covering the parts of my Rails code that need to be covered pretty well. Since I still use scaffolding, I don’t think testing adds a whole lot of time to my development cycle, and if anything I see it saving time down the road when tracking down errors that might not be found with old school browser-side testing. I know I’ve got some things to improve upon, particularly in user interface testing, but I feel like I can continue down that road once I’m sure that my applications’ underpinnings are sound.

Retrofitting old applications

Over the last few months I’ve been revisiting projects I still support but didn’t necessarily do a great job of testing, putting my system to use to check my work by writing tests and seeing if they actually pass the way I expect they should. I work backwards in these cases, testing my models with RSpec and then writing behavior tests. Interestingly, I do find things that I’ve missed from time to time that I’m surprised haven’t already come back to bite me in implementation, but it’s better that they’re found here than by an end user.

Retrofitting your existing applications is also a good way to learn the syntaxes and nuances of your chosen testing frameworks, since you should have a pretty good idea of how they’re currently working–that way when a test doesn’t pass, and you know it’s supposed to, you can focus more of your attention on the test you’ve written as opposed to the code you’ve written that should make it pass.

Try to dedicate a portion of your day or week to revisiting old projects and bolstering them through tests. It’s a good learning exercise and can save you a lot of time and embarrassment down the road.

How do you test?

Like I said, I think the best way to embrace testing is to find a method that works best for you–so what’s yours? Are you by the book? If not, what parts of the workflow have you customized? If you’re not testing, what’s stopping you?

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