Short discussion on Mocks and Stubs for RSpec study group. Done by thefonso.

1. Review
Terminology
Thursday, August 9, 12

2. Mocks and Stubs
http://rubydoc.info/gems/rspec-mocks/
• A Method Stub returns a pre-determined value.
• A Mock Object is a Test Double that supports message
expectations and method stubs
• Why should you care?
Thursday, August 9, 12

3. Expectations
http://rubydoc.info/gems/rspec-expectations/RSpec/Expectations
• should
• should_not
• should_receive
• should_not_receive
• expect
Thursday, August 9, 12

4. Method Stubs
http://rubydoc.info/gems/rspec-mocks/
• A method stub returns a pre-determined value.
• rspec-mocks supports 3 forms for declaring method stubs:
book.stub(:title) { "The RSpec Book" }
book.stub(:title => "The RSpec Book")
book.stub(:title).and_return("The RSpec Book")
Thursday, August 9, 12

5. Mocks
http://rubydoc.info/gems/rspec-mocks/
• A Mock Object is a Test Double that supports message
expectations and method stubs
• Mock Object example...
Thursday, August 9, 12

6. class Zombie < ActiveRecord::Base
has_one :weapon
def decapitate
weapon.slice(self, :head)
self.status = "dead again"
end
end
Thursday, August 9, 12

7. describe Zombie do
let(:zombie) { Zombie.create }
context "#decapitate" do
it "calls weapon.slice" do
zombie.weapon.should_receive(:slice)
zombie.decapitate
end
it "sets status to dead again" do
zombie.weapon.stub(:slice)
zombie.decapitate
zombie.status.should == "dead again"
end
end
end
Thursday, August 9, 12

8. Exercise
Use resource links and write some test
Thursday, August 9, 12

9. Resources:
Book:
• http://www.amazon.com/The-RSpec-Book-Behaviour-Development
Online:
• http://rubydoc.info/gems/rspec-expectations/RSpec/Expectations
• http://rubydoc.info/gems/rspec-expectations/RSpec/Matchers
• http://rubydoc.info/gems/rspec-mocks/
Thursday, August 9, 12