Baldowl

my nest somewhere in GitHub's forest

Coercing Cucumber And Webrat To Cooperate

After the release of Ruby on Rails 3, using Webrat with Cucumber in a Ruby on Rails 3 application is not something that works out of the box as before.

The following assumes Cucumber 0.9.4, Cucumber-rails 0.3.2 and Webrat 0.7.2.

Rack mode

First of all, if we let Cucumber’s generator do its work, we get an env.rb file which is unsuitable for Ruby on Rails 3: the Webrat’s mode is wrong. We can edit that file, trusting that our VCS will help us to recover the needed modifications next time we upgrade Cucumber, or we can drop a new file in features/support/ and override the configuration:

Rack::Test

Then we have to fix Rack::Test, which is used by Webrat’s Rack mode and Rails’s integration testing classes. What’s wrong with it?

Webrat and Rails use “example.com” as default host; Rack::Test uses “example.org” as default host in the fake session automatically built by its methods which simulate HTTP requests. This difference influences negatively Webrat’s capability to follow the usual, “internal” redirection which usually comes after, for example, record updates: the hosts do not match, so the redirection is not considered an internal one and Webrat does not follow it.

We must redefine a Rack::Test’s constant; Ruby will produce a warning, but it’s harmless noise in this case.

Update 2011-03-07: A reader kindly reminded me about Kernel::silence_warnings, so you can optionally redefine that Rack::Test’s constant as follows and never see that noise again:

Please, beware of the peril of “playing with constants” and don’t blame neither of us if your application blows up misteriously :-) any time later.

HTML5 data attributes

So now we have almost everything working again… until we smash into the following problem.

Let’s say we have a list of records, each paired with a “Delete” link. We have the following scenario, spiced up with the help of Pickle:

We run Cucumber and the scenario does not pass. Webrat uses link’s onclick to decide if GET or something else must be used, but Ruby on Rails 3 does not produce the same, old HTML code: it now embraces the unobtrusiveness way of life, so it got rid of onclick attributes and replaced them with HTML5 data attributes:

Until a fix emerges for this, a workaround could be something like the following step definition:

The happy end

There’s no doubt that life was simpler in the old days of Ruby on Rails 2 :-) but with just a bunch of tweaks everything works almost as before and things will probably get better as the dust settles.

blog comments powered by Disqus