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Introducing StepSpecr

By matthias

StepSpecr is a Rails plugin intended to be used with Rspec User Stories.

StepSpecr provides a ‘testing’ framework for speccing Given/When/Then steps within Rspec examples. This lets you implement GWT-steps the BDD way.

Getting started

StepSpecr is a Rails plugin, so…

$ rails greatapp

$ cd greatapp

It’s necessary to have edge rails in order to use the plugin script with github (where stepspecr is hosted).

$ rake rails:freeze:edge

StepSpecr depends on rspec:

$ script/plugin install git://github.com/dchelimsky/rspec.git

$ script/plugin install git://github.com/dchelimsky/rspec-rails.git

$ script/generate rspec

Install StepSpecr:

$ script/plugin install git://github.com/mhennemeyer/stepspecr.git

$ script/generate stepspecr

Run the example_step_spec

By bootstraping the project (script/generate stepspecr) a example_step_spec.rb was generated. Run it now to see if everything works.

$ script/spec—format -c specdoc spec/steps/example_step_spec.rb

( I'll work on performance :) )

Spec a great step

Create a new spec file:

$ mate greatapp/spec/steps/great_step_spec.rb

The spec needs to require its helper file:

require File.expand_path(File.dirname(FILE) + ”/stepspecr_helper.rb”)

(You can copy it from the example_step_spec.)

The greatapp must have a great model to work properly

so you’ll likely write the following step in your Rspec Story:

Given a great_model

Write an example for this step:

In PROJECT_HOME/spec/steps/great_steps_spec.rb:


  require File.expand_path(File.dirname(__FILE__) + "/stepspecr_helper.rb")

  describe "Given a great_model" do
    it "should create a great_model" do
      StepSpecr.spec "Given a great_model" do 
        step_group :great_models
        before do 
          class GreatModel 
          end
          GreatModel.should_receive(:create)
        end
      end
    end
  end

The code passed to the before method in the spec block will be evaluated before the ‘Given a great_model’ step gets run.
We only want to specify what the step will do and we don’t care about if there is a GreatModel class in the system. – so we can just ‘mock’ one.
The second statement in the before block is the actual expectation we have of the behavior of the step: It should try to create a GreatModel instance.
Run the example and watch it fail:

$ script/spec—format -c specdoc spec/steps/great_steps_spec.rb

Implementation.

Create the step file:

$ mate greatapp/stories/steps/great_steps.rb

The failure message was: ‘Didn’t find step’. Let’s write the step without implementation to get a more meaningful directive:


  steps_for :great_models do
    Given "a great_model" do
    end
  end

Run the example again:

$ script/spec—format specdoc spec/steps/great_step_spec.rb

Now the system tells us what to do: ‘Mock expected :create … ‘


  steps_for :great_models do
    Given "a great_model" do
      GreatModel.create
    end
  end