Sample Unit Tests

user.rb

class User < ActiveRecord::Base
  # Validation
  validates_presence_of :password_confirmation 
  # Association
  has_many :comments
  # Instance Method
  def full_name
    "#{first_name} #{last_name}"
  end
end

user_test.rb

context "A User" do
  # Validation specification
  specify "should require password confirmation" do
    u = create_user(:password_confirmation => nil)
    u.should.not.validate
    u.errors.on(:password_confirmation).should.not.be.blank
  end
  # Association specification
  specify "should know about his comments" do
    u = create_user(
      :comments => [
      { :body => 'you rock!' },
      { :body => 'i know it!' }
      ])
    u.comments.count.should.be 2
  end
  # Instance method specification
  specify "should format full name properly" do
    u = create_user(:first_name => "George", :last_name => "Michael")
    u.full_name.should.equal  "#{u.first_name} #{u.last_name}"
  end
end