Introduction à RSpec

I presented RSpec at OpenCode #8.

Transcript

1. RSpec
   Rémi Prévost — OpenCode #8
   

   View Slide

2. “
   RSpec is a
   Behaviour-Driven
   Development tool for
   Ruby programmers
   ”
   

   View Slide

3. Teste le
   comportement et
   non la finalité des
   objets
   

   View Slide

4. Langage naturel,
   écrire le moins de
   texte possible dans
   nos tests
   

   View Slide

5. Test::Unit
   vs.
   RSpec
   gem install rspec
   

   View Slide

6. require "test/unit"
   class ProductTest < Test::Unit::TestCase
   def test_initial_quantity
   assert_equal 4, Product.new.initial_quantity
   end
   end
   describe Product do
   subject { Product.new }
   its(:initial_quantity) { should eq 4 }
   end
   

   View Slide

7. Matchers
   Goodbye asserts!
   

   View Slide

8. describe Array do
   subject { [1, 2, 3, 4] }
   # Teste subject.size
   its(:size) { should eq 4 }
   # Teste subject.empty?
   it { should_not be_empty }
   # Teste subject.size, subject.clear et subject.size encore
   it do
   expect { subject.clear }.to change(subject, :size).to(0)
   end
   end
   

   View Slide

9. % rspec array_spec.rb
   ...
   Finished in 0.00454 seconds
   3 examples, 0 failures
   

   View Slide

10. % rspec array_spec.rb --format documentation --colour
    Array
    should not be empty
    should change size
    size
    should eq 4
    Finished in 0.00316 seconds
    3 examples, 0 failures
    

    View Slide

11. describe Array do
    subject { [1, 2, 3, 4] }
    # Teste subject.size
    its(:size) { should eq 3 }
    end
    

    View Slide

12. % rspec array_spec.rb --format documentation --colour
    Array
    size
    should eq 3 (FAILED - 1)
    Failures:
    1) Array size
    Failure/Error: its(:size) { should eq 3 }
    expected: 3
    got: 4
    (compared using ==)
    Finished in 0.0009 seconds
    1 example, 1 failure
    Failed examples:
    rspec ./array_spec.rb:7 # Array size
    

    View Slide

13. "foo".should eq "foo"
    # "foo" == "foo"
    Product.new.should be_available
    # Product.new.available? == true
    Product.new.should be_instance_of(Product)
    # Product.new.instance_of?(Product)
    "foo".should respond_to(:upcase)
    # "foo".respond_to?(:upcase)
    { :foo => "bar" }.should have_key(:foo)
    # { :foo => "bar" }.has_key?(:foo)
    [1, 2, 3].should have(3).items
    # [1, 2, 3].size == 3
    

    View Slide

14. expect { 42/0 }.to raise_error(ZeroDivisionError)
    # &block.call rescue ZeroDivisionError
    @a = [1, 2, 3, 4]
    expect { @a.clear }.to change{ @a.length }.from(4).to(0)
    # &block.call == 4
    # &expectation.call
    # &block.call == 0
    @a = [1, 2, 3, 4]
    expect { @a.clear }.to change(@a, :length).from(4).to(0)
    # @a.length == 4
    # &expectation.call
    # @a.length == 0
    

    View Slide

15. Contextes
    

    View Slide

16. describe Product do
    context "without supply" do
    subject { Product.new(:quantity_left => 0) }
    it { should be_sold_out }
    end
    context "with supply" do
    subject { Product.new(:quantity_left => 10) }
    it { should_not be_sold_out }
    end
    end
    

    View Slide

17. describe Product do
    describe :build do
    context "as admin user" do
    before { @user = User.new(:roles => [:admin]) }
    context "without scope" do
    subject { Product.build(:as => @user) }
    its(:owner) { should eq @user }
    it { should_not be_available }
    end
    context "with available scope" do
    subject { Product.available.build(:as => @user) }
    its(:owner) { should eq @user }
    it { should be_available }
    end
    end
    end
    end
    

    View Slide

18. Variables
    

    View Slide

19. describe Product do
    describe :similar_products do
    context "without supply" do
    subject { Product.new }
    it "returns the next sold out product" do
    subject.similar_products(10).first.should be_sold_out
    end
    end
    context "with supply" do
    subject { Product.new(:quantity_left => 5) }
    it "returns the next available product" do
    subject.similar_products(10).first.should_not be_sold_out
    end
    end
    end
    end
    

    View Slide

20. describe Product do
    describe :similar_products do
    let(:next_product) { subject.similar_products(10).first }
    context "without supply" do
    subject { Product.new }
    specify { next_product.should be_sold_out }
    end
    context "with supply" do
    subject { Product.new(:quantity_left => 5) }
    specify { next_product.should_not be_sold_out }
    end
    end
    end
    

    View Slide

21. Rails
    gem install rspec-rails
    gem install shoulda
    

    View Slide

22. Modèles
    

    View Slide

23. describe Product do
    describe :Associations do
    # TODO
    end
    describe :Validations do
    # TODO
    end
    describe :Callbacks do
    # TODO
    end
    describe :InstanceMethods do
    # TODO
    end
    describe :ClassMethods do
    # TODO
    end
    end
    

    View Slide

24. describe Product do
    describe :Associations do
    it { should belong_to(:brand) }
    it { should have_many(:pictures) }
    end
    end
    class Product < ActiveRecord::Base
    belongs_to :brand
    has_many :pictures
    end
    

    View Slide

25. describe Product do
    describe :Validations do
    it { should validate_presence_of(:name) }
    it { should ensure_inclusion_of(:state).in(%w{visible hidden}) }
    it { should_not allow_value("_$#!").for(:sku) }
    end
    end
    class Product < ActiveRecord::Base
    validates :name, :presence => true
    validates :state, :inclusion => { :in => %w{visible hidden} }
    validates :sku, :rosette_sku => true
    end
    

    View Slide

26. describe Product do
    describe :Callbacks do
    describe :adjust_sold_out_flag do
    subject { Product.new(:sold_out => false) }
    specify do
    subject.quantity_left = 0
    expect {
    subject.save!
    }.to change(subject, :sold_out?).from(false).to(true)
    end
    end
    end
    end
    class Product < ActiveRecord::Base
    before_save :adjust_sold_out_flag, :if => proc {
    self.quantity_left_changed? and self.quantity_left == 0
    }
    end
    

    View Slide

27. describe Product do
    describe :Callbacks do
    describe :adjust_sold_out_flag do
    subject { Product.new(:sold_out => false) }
    before { subject.quantity_left = 0 }
    specify do
    subject.should_receive(:adjust_sold_out_flag).once
    subject.save!
    end
    end
    end
    end
    class Product < ActiveRecord::Base
    before_save :adjust_sold_out_flag, :if => proc {
    self.quantity_left_changed? and self.quantity_left == 0
    }
    end
    

    View Slide

28. Contrôleurs
    

    View Slide

29. describe ProductsController do
    # POST /products
    describe :create do
    end
    # GET /products
    describe :index do
    end
    # PUT /products/:id
    describe :update do
    end
    # GET /products/:id
    describe :show do
    end
    # DELETE /products/:id
    describe :destroy do
    end
    end
    

    View Slide

30. describe ProductsController do
    # POST /products
    describe :create do
    before do
    post :create, :product => { :name => "Foo" }
    end
    it { should redirect_to(products_path) }
    it { should set_the_flash[:notice].to("Yay!") }
    end
    end
    class ProductsController < ApplicationController
    def create
    if Product.create(params[:product])
    flash[:notice] = "Yay!"
    redirect_to products_path
    end
    end
    end
    

    View Slide

31. class ProductsController < ApplicationController
    def create
    if Product.create(params[:product])
    flash[:notice] = "Yay!"
    redirect_to products_path
    else
    flash[:error] = "Nope!"
    end
    end
    end
    

    View Slide

32. describe ProductsController do
    # POST /products
    describe :create do
    let :create_product! { post :create, :product => attrs }
    context "with valid attributes" do
    let(:attrs) { { :name => "Foo" } }
    before { create_product! }
    it { should redirect_to(products_path) }
    it { should set_the_flash[:notice].to("Yay!") }
    end
    context "with invalid attributes" do
    let(:attrs) { { :name => "" } }
    before { create_product! }
    it { should render_template("products/create") }
    it { should set_the_flash[:error].to("Nope!") }
    end
    end
    end
    

    View Slide

33. describe ProductsController do
    # GET /products
    describe :index do
    before do
    @product = stub_model(Product)
    Product.stub(:all).returns([@product])
    get :index
    end
    it { should respond_with(:success) }
    it { should render_template("products/index") }
    it { should assign_to(:products).with([@product]) }
    end
    end
    class ProductsController < ApplicationController
    def index
    @products = Product.all
    end
    end
    

    View Slide

34. describe "products/index" do
    before do
    assign(:products, [stub_model(Product, :name => "Foo")])
    render
    end
    it { expect(rendered).to include("Foo") }
    end
    
    
    
    Vues
    

    View Slide

35. describe "GET /products" do
    it do
    expect(:get => "/products").to route_to(
    :controller => "products",
    :action => "index"
    )
    end
    end
    resources :products
    Routes
    

    View Slide

36. describe ProductsHelper do
    describe :format_price do
    subject do
    helper.format_price(stub_model(Product, :price => 1200))
    end
    it { should eq "$12.00" }
    end
    end
    module ProductsHelper
    def format_price(product)
    Money.new(product.price).format
    end
    end
    Helpers
    

    View Slide

37. Merci!
    Questions? Commentaires?
    

    View Slide