Rails%203%20In%20Action

2.3.1 RSpec
Bacon.edible?.should be_true
end
end
Behavior-driven development
The benefits of writing tests like this are that clients can understand precisely what
the test is testing and then use these steps in acceptance testing; 5 a developer can
read what the feature should do and then implement it; and finally, the test can be
run as an automated test. With tests written in DSL, you have the three important elements
of your business (the clients, the developers, and the code) all operating in the
same language.
RSpec is an extension of the methods already provided by Test::Unit. You can even
use Test::Unit methods inside of RSpec tests if you wish. But we’re going to use the
simpler, easier-to-understand syntax that RSpec provides.
Cucumber tests are written in a language called Gherkin, which goes like this:
Given I am reading a book
When I read this example
Then I should learn something
Each line indicates a step. The benefit of writing tests in the Gherkin language is that
it’s closer to English than RSpec is, making it even easier for clients and developers to
read.
RSpec is a BDD tool written by Steven R. Baker and now maintained by David Chelimsky
as a cleaner alternative to Test::Unit, with RSpec being built as an extension to
Test::Unit. With RSpec, you write code known as specs that contain examples, which are
synonymous to the tests you know from Test::Unit. In this example, you’re going to
define the Bacon constant and then define the edible? method on it.
Let’s jump right in and install the rspec gem by running gem install rspec. You
should see the following output:
Successfully installed rspec-core-2.6.4
Successfully installed rspec-expectations-2.6.4
Successfully installed rspec-mocks-2.6.4
Successfully installed rspec-2.6.4
You can see that the final line says the rspec gem is installed, with the version number
specified after the name. Above this line, you also see a thank-you message and,
underneath, the other gems that were installed. These gems are dependencies of the
rspec gem, and as such, the rspec gem won’t work without them.
When the gem is installed, create a new directory for your tests called bacon anywhere
you like, and inside that, create another directory called spec. If you’re running
a UNIX-based operating system such as Linux or Mac OS X, you can run the
mkdir -p bacon/spec command to create these two directories. This command will
5 A process whereby people follow a set of instructions to ensure a feature is performing as intended.
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