This document provides an overview of RSpec, a testing framework for Ruby. It discusses key components of RSpec like Core, Expectations, and Mocks. It describes how to run RSpec specs with Rake tasks or directly from the command line. It explains matchers like "be" and "have" that are used to make assertions in RSpec examples. It also covers subjects, lets, contexts, class/instance methods, model validations, mocks, and how to test rails models and mailers using RSpec.

1. RSpec
documentation
http://relishapp.com/rspec

2. components
RSpec Core
RSpec Expectations
RSpec Mocks
RSpec Rails

3. run specs
rake spec
rake spec:models
rspec spec/models/order_spec.rb
rspec spec/models/order_spec.rb:19

4. "be" matchers
describe 0 do
it { subject.zero?.should == true }
# vs.
it { should be_zero } # 0.zero? == true
end

5. have(n).items matcher
collection.should have(x).items
collection.should have_at_least(x).items
collection.should have_at_most(x).items
it { should have(5).line_items }

6. subject

7. implicit subject
describe Comment do
subject { Comment.new }
end

8. explicit subject
describe Order do
subject { Factory.build(:order) }
end

9. implicit receiver
it { subject.should be_valid }
# vs.
it { should be_valid }

10. its
its(:status_name) { should == :draft }
its('line_items.count') { should == 5 }

11. let
before do
@order = Factory.create(:shipped_order)
end
# vs.
let(:order) do
Factory.create(:shipped_order)
end

12. context vs. describe
alias :context :describe
describe is for methods
context is for contexts

13. class & instance methods
describe '#title' do # instance method
...
end
describe '.title' do # class method
...
end

14. context
context 'when quantity is negative' do
before { subject.quantity = -1 }
...
end

15. model validations
it { should be_invalid }
its(:errors) { should be_present }
it { should have(1).errors_on(:quantity) }

16. shoulda-matchers
it 'should validate email and quantity' do
subject.email = 'test@example.com'
subject.quantity = -1
subject.valid?
should have(:no).errors_on(:email)
should have_at_least(1).error_on(:quantity)
end
# vs.
it { should allow_value('test@example.com').for(:email) }
it { should_not allow_value(-1).for(:quantity) }

17. mocks
fake objects and methods
don't touch database
faster specs

18. rails model mocks
mock_model is a test double that acts like an
ActiveModel
stub_model is a instance of a real
ActiveModel with some methods stubbed

19. using mocks
let(:email_template) do
stub_model(EmailTemplate,
:name => 'test_email', ...)
end
before do
...
EmailTemplate.stub(:find_by_name).
with('test_email').
and_return(email_template)
end

20. message expectation
def should_deliver_mail(method)
Mailer.should_receive(method).
with(subject).
and_return(double(:deliver => nil))
end

21. questions?