How to reuse scenarios within different features with rspec + capybara - ruby-on-rails-3

Question

Say I have some scenarios that I want to test under different contexts, or "features".
For example, I have scenarios which involve the user visiting certain pages and expecting certain ajax results.
But, under different conditions, or "features", I need to perform different "background" tasks which change the state of the app.
In this case I need to run the same scenarios over and over again to make sure that everything works with the different changes to the state of the app.
Is there a way to define scenarios somewhere, and then reuse them?

Answer 1

You can create re-usable scenarios that are used in multiple features by using shared examples.
A basic example, taken from the relishapp page is below. As you can see, the same scenarios are used in multiple features to test different classes - ie there are 6 examples run.
require 'rspec/autorun'
require "set"
shared_examples "a collection" do
let(:collection) { described_class.new([7, 2, 4]) }
context "initialized with 3 items" do
it "says it has three items" do
collection.size.should eq(3)
end
end
describe "#include?" do
context "with an an item that is in the collection" do
it "returns true" do
collection.include?(7).should be_true
end
end
context "with an an item that is not in the collection" do
it "returns false" do
collection.include?(9).should be_false
end
end
end
end
describe Array do
it_behaves_like "a collection"
end
describe Set do
it_behaves_like "a collection"
end
There are several examples on the relishapp page, including running the shared examples with parameters (copied below). I would guess (since I do not know your exact tests) that you should be able to use the parameters to setup the different conditions prior to executing the set of examples.
require 'rspec/autorun'
shared_examples "a measurable object" do |measurement, measurement_methods|
measurement_methods.each do |measurement_method|
it "should return #{measurement} from ##{measurement_method}" do
subject.send(measurement_method).should == measurement
end
end
end
describe Array, "with 3 items" do
subject { [1, 2, 3] }
it_should_behave_like "a measurable object", 3, [:size, :length]
end
describe String, "of 6 characters" do
subject { "FooBar" }
it_should_behave_like "a measurable object", 6, [:size, :length]
end