RSpec crash course.

Readme.md

• specs go in the "spec" directory
• specs end in "_spec.rb"
• toplevel begins with describe
• inside of a describe you have an it
• example is an alias for it
• inside of it blocks, you write your code and assertions
• run with $ rspec or $ rspec spec/some_spec.rb
• if you need common setup (e.g. add another dir to the load path), put into "spec/spec_helper.rb" and then `require "spec_helper" at the top of the spec
• using let will allow you to name a value that you want to call from your spec, it will only be calculated once per spec. It will not be called until you invoke it.
• before will run before each spec, you can set variables / establish state (e.g. put values into a db)
• describes can be nested inside of each other.

divider.rb

class Divider
  def self.div2(n)
    n / 2
  end
end

example_spec.rb

require 'spec_helper'

describe "my example" do
  it "passes" do
    1.should == 1
  end

  it "fails" do
    1.should == 2
  end

  example "times2" do
    Multiplier.times2(3).should == 6
  end

  example "div2" do
    Divider.div2(6).should == 3
  end

  before do
    @num1 = 5
  end
  let(:num2) { 10 }
  # this is approximately the same as
  # def num2
  #   @num2 ||= 10
  # end
  example "using before and let blocks" do
    Multiplier.times2(@num1).should == num2
  end

  describe 'nested' do
    it 'works in here too' do
      true.should == true
    end
  end
end

multiplier.rb

class Multiplier
  def self.times2(n)
    n * 2
  end
end

spec_helper.rb

require 'multiplier'

$LOAD_PATH.unshift(File.expand_path('../../lib2', __FILE__))
require 'divider'