Rails on the Run

Rails experiments by Matt Aimonetti

Browsing Posts tagged testing

Like most people who started with Rails a while back, I first loved Rails fixtures and ended up hating them (slow, a pain to maintain etc…).

I went through different experiments, trying different existing libs, writing my own solutions etc… I wasn’t quite satisfied until I found factory_girl from thoughtbot.

You might not feel the need for a decent fixtures solution if you do a lot of mocking/stubbing, but I recently came back from my “mock everything you can outside of models” approach and I’m getting closer to the mock roles, not objects approach. So, I’m loosing my model/controller testing separation but I’m gaining by not having to maintain “dumb mocks” which don’t always represent the real API behind. I mean, how many times did I change a Model, messing up my app but all my specs were still passing. Anyway, that’s a long discussion, which will be covered by wycats during merbcamp

So here is a simple example of how I use factory girl in a Merb + DataMapper app. (you can do the same in a Rails app, there is nothing specific to Merb in factory_girl).

  • I. create an empty app, set the ORM etc…
  • II. git pull and install factorygirl from http://github.com/thoughtbot/factorygirl/tree/master. Or install thoughtbot-factory_girl gem using GitHub gem server.
  • III. create a spec/factories.rb file. (You might prefer to create a folder called spec/factories and add a factory per model)
  • IV. modify spec_helper.rb and add the following
  require 'factory_girl'
  require File.dirname(__FILE__) + '/factories/index.html'
  • V. write some specs against a Client model

  • VI. Create the Model

  • VII. create a factory

  • IIX. run your specs

    failing specs

  • IX. fix the model (note that I set dependencies "dm-validations" in my init.rb)

  • X. run the specs

    passing specs

  • XI. add more specs

As you can see, Factory.build(:client) only creates a new instance of the Object, while Factory(:client) creates, saves and loads the instance.

  • XII. get them to pass

Factory Girl makes fixtures simple and clean. Here is another example for creating associations:

Factory Girl also supports sequencing, check out FG read me

In conclusion, Factory Girl is a mature and solid factory solution which will take you less than 15 minutes to get used to. It will offer you loads of flexibility and less frustration than good old yaml fixtures. You can also use it with existing fixtures if you want to start using it in an existing app.

I haven’t posted for quite a long time. The thing is I moved to a new place and I’m really busy on working clients + setting up my new office + dealing with way too much paperwork.

Anyway, enough excuses, here are few tips that I believe will be useful to some of you:

ZenTest Autotest

I love autotest, but you might have noticed that sometimes (especially on big projects), ZenTest might start using more CPU than expected. On my machine, that results in the fan going off and annoying the crap out of me.

The solution is quite simple, exclude all folders you don’t need to monitor. To do that, update ZenTest to version 3.8.X

sudo gem update ZenTest

(older version had a different syntax)

Now, edit your .autotest that should be located in ~/.autotest (if it doesn’t exist, create it).

Finally add the following code:

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  Autotest.add_hook :initialize do |at|
    %w{.svn .hg .git vendor}.each {|exception| at.add_exception(exception)}
  end

I personally freeze rails in vendor and I autotest is way happier when it doesn’t have to monitor some extra files. (note that we also exclude folders such as .git or .svn)
(you can also include files etc… read more there)

RSpec

RSpec is certainly my favorite Ruby tool and I’m glad to say that most of my SD.rb friends finally got convinced!

Now, few people complained to me about spec failures outputting the full stack such as:

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 The Sessions controller should fail since it's a test' FAILED
 expected true, got false
 test_app-git/trunk/vendor/plugins/rspec/lib/spec/expectations.rb:52:in `fail_with'
 test_app-git/trunk/vendor/plugins/rspec/lib/spec/expectations/handler.rb:21:in `handle_matcher'
 test_app-git/trunk/vendor/plugins/rspec/lib/spec/expectations/extensions/object.rb:34:in `should'
 ./spec/controllers/sessions_controller_spec.rb:25:
 test_app-git/trunk/vendor/plugins/rspec/lib/spec/example/example_methods.rb:78:in `instance_eval'
 test_app-git/trunk/vendor/plugins/rspec/lib/spec/example/example_methods.rb:78:in `run_with_description_capturing'
 test_app-git/trunk/vendor/plugins/rspec/lib/spec/example/example_methods.rb:19:in `execute'
 /opt/local/lib/ruby/1.8/timeout.rb:48:in `timeout'
 test_app-git/trunk/vendor/plugins/rspec/lib/spec/example/example_methods.rb:16:in `execute'
 test_app-git/trunk/vendor/plugins/rspec/lib/spec/example/example_group_methods.rb:288:in `execute_examples'
 test_app-git/trunk/vendor/plugins/rspec/lib/spec/example/example_group_methods.rb:287:in `each'
 test_app-git/trunk/vendor/plugins/rspec/lib/spec/example/example_group_methods.rb:287:in `execute_examples'
 test_app-git/trunk/vendor/plugins/rspec/lib/spec/example/example_group_methods.rb:121:in `run'
 test_app-git/trunk/vendor/plugins/rspec/lib/spec/runner/example_group_runner.rb:22:in `run'
 test_app-git/trunk/vendor/plugins/rspec/lib/spec/runner/example_group_runner.rb:21:in `each'
 test_app-git/trunk/vendor/plugins/rspec/lib/spec/runner/example_group_runner.rb:21:in `run'
 test_app-git/trunk/vendor/plugins/rspec/lib/spec/runner/options.rb:89:in `run_examples'
 test_app-git/trunk/vendor/plugins/rspec/lib/spec/runner/command_line.rb:19:in `run'
 script/spec:4:

  Finished in 6.035147 seconds

  400 examples, 1 failure

We can really easily change that, open you spec.opts file located in your spec folder.

it probably looks like that:

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  --colour
  --format
  progress
  --loadby
  mtime
  --reverse
  --backtrace

Get rid of “–backtrace” and your new failure should look like:

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  1)
  'The Sessions controller The Sessions controller should fail since it's a test' FAILED
  expected false, got true
  ./spec/controllers/sessions_controller_spec.rb:25:
  script/spec:4:

  Finished in 0.269956 seconds

  15 examples, 1 failure
  

Other stuff you may find interesting (in no particular order):

RSpec is an awesome testing framework. On top of being the first Ruby BDD framework the core team is doing a great job in enhancing our testing experience and therefore the quality of our code.

This time, I don’t want to introduce to the latest changes but instead showing you what Josh Knowles, Bryan Helmkamp and myself came up with.

RSpec on Rails matchers plugin + TextMate Bundle

Matchers are some sort of helpers that will help you cleaning up your tests. We simply came up with a collection of matchers that we think will make your like easier.

We divided the matchers in 3 categories:

Associations

Verify that the association has been defined. (doesn’t verify that the association works!)

Usage examples:

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    @post.should have_many(:comments)
  
    @comment.should belong_to(:post)
  
    @user.should have_one(:social_security_number)
  
    @project.should have_and_belong_to_many(:categories)

Validations

Verify that a validation has been defined. (doesn’t test the validation itself)

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    object.should validate_presence_of(:attribute)

    object.should validate_confirmation_of(:attribute)

    object.should validate_uniqueness_of(:attribute)

    object.should validate_length_of(:attribute, :between => 5..10)
    
    object.should validate_length_of(:attribute, :is => 5)

Views

My personal favorite matchers, you can now do stuff like:

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    it "should render new form" do
        render "/users/new.html.erb"

        response.should have_form_posting_to(users_path) do
          with_text_field_for(:user_name)
          with_text_area_for(:user_address)
          with_text_field_for(:user_login)
          with_text_field_for(:user_email)
          with_submit_button
        end
    end

Check the readme for more information and details on the added matchers. I personally recommend you try the TextMate Bundle on top of being a perfect tool for lazy devs, it also lists all the available matchers and is an excellent way of learning.

We just released our first release yesterday, this is not a final version and we will keep on improving the code. If you have suggestions and patches feel free to open a ticket there.