[rspec-users] Why RSpec?

Andrew Vit andrew at avit.ca
Wed Apr 22 12:52:24 EDT 2009

On Apr 22, 2009, at 4:25 AM, Amos King wrote:

> I wasn't thinking about a gun.  I was just wondering if there is some
> underlying reason that I'm missing.  Is there a background structure
> that I'm not grasping?  Is there a huge piece of functionality that
> I'm missing?  Is it faster than Test:Unit or Shoulda?
> Amos(adkron)

Personally, I can't think of one single huge piece of functionality  
that makes RSpec win over TestUnit, but it's a whole bunch of little  

It can be faster if you make use of mocks/stubs, and separation  
between layers: you can test your controllers without having to render  
the views.

Shoulda is good too. It adds some of the features that RSpec brought,  
like contexts, but having used Shoulda for over a year and recently  
using RSpec on a new project, I can say that I prefer RSpec overall...  
keep in mind Shoulda's macros and matchers are available in RSpec too.

describe RSpec, "versus TestUnit" do
   it { should read_fluently }

Yes, a lot of the most visible differences seem to be around the  
syntax, but the point is that it helps you think more fluidly about  
what you're actually trying to do. TestUnit adds mental baggage for up- 
front testing and the tests have a backward-looking feel, in other  
words, they read more like they're verifying what should have happened  
after it's done. RSpec tests read more expressively as looking forward  
to what you would like to achieve, what "should" happen.

While the tests are still pure ruby, they read almost like pure  
English, especially if you take a little extra effort to encapsulate  
some of the hairy logic into your own custom matchers. The specs can  
convey their intent much more clearly, instead of only serving as  
verification of your app's performance. Your spec suite becomes very  
readable (to a developer at least) as behaviour documentation, without  
needing to slow down to work it out too much. That's not to say you  
can't write readable tests in Shoulda or TestUnit, but RSpec helps you  
frame them better and convey what you mean more clearly.

Andrew Vit

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