RSpec Explained

describe

• defines a context
• takes a class or a string as its name

it

• defines an example (aka spec or test)

should

• defines an assertion
• every test needs at least one assertion
  • or else you're not really testing anything

matchers

• passed to should
• perform a test on the object that should is called on

be matchers

@@@ ruby
[].should be_empty

• uses method_missing magic
• be_empty invokes empty? on its target
• be_valid invokes valid? on its target
• and so on

before and after

@@@ruby
before do
  @data = [1,2,3]
end

• defines some code that will be executed before each of the specs in that describe block
• there's also before :all do..end which executes only once
• there's also after with similar semantics