Testing 101: A night out with factory girl

Going over factory girl basics and some of the more advanced features

Transcript

1. Testing 101: A night out with FactoryGirl
2. Me Twitter: @BradleyTemple Github: DVG Neo Hack Nights: That Testing Guy from Chase
3. What’s FactoryGirl? • At it’s most basic: Makes objects for tests.
4. Basic Factories factory :user do username “Bob” age 30 end “Snapshot” of object data that’s reusable in tests
5. Basic Factories Associations factory :post do title “Hi!” body “Hello!” user end Makes an object of the factory named the same thing
6. Basic Factories Sequences factory :user do sequence(:username) { |n| “user#{n}” } age 30 end Automatically increments the attribute to take care of uniqueness constraints
7. Basic Factories Attribute blocks factory :user do sequence(:username) { |n| “user#{n}” } age 30 password “secret” password_confirmation { |u| u.password } end
8. Basic Factories Child Factories factory :user do sequence(:username) { |n| “user#{n}” } admin false factory :admin do admin true end end
9. Okay, let’s start looking at awesome stuff
10. Stay outta the database! build_stubbed(:admin) Creates mock object based on attributes defined in the factory Will throw an exception if your test attempts to interact with the database at all
11. Named Associations class Message < ActiveRecord::Base belongs_to :sender, class_name: “User”, foreign_key: “sender_id” belongs_to :recipient, class_name: “User”, foreign_key: “recipient_id” end
12. Aliases! factory :user, aliases: [:sender, :recipient] do username “Bob” age 30 end factory :message do sender recipient end
13. Traits factory :user do username “Bob” age 30 trait :voting_age do age 18 end trait :drinking_age do age 21 end end
14. Using Traits drinking_buddy = create(:user, :drinking_age) Method One: Called Directly Method Two: Child Factory factory :user do username “Bob” age 30 trait :drinking_age do age 21 end factory :drinking_buddy, :traits => [:drinking_age] end
15. Combining Traits factory :user do username “Bob” age 30 trait :drinking_age do age 21 end trait :admin do admin true end factory :go_home_admin_your_drunk, :traits => [:drinking_age, :admin] end This is like factory multiple inheritance
16. Usage create(:go_home_admin_your_drunk) # => User(username: “user_1”, admin: true, age: 21)
17. To-Many Relationships # Objectively Bad Way user = create(:user) 5.times { create(:post, user: user)
18. Ignored Attributes & Callbacks factory :user do sequence(:username) { |n| “user#{n}” } age 30 factory :user_with_posts do ignore do post_count 1 end after(:create) do |user, factory| create_list :post, factory.post_count, user: user end end end
19. Usage create(:user_with_posts, post_count: 1) # => User (username: “user_1”, posts: [ Post(title: “Hello World”)])
20. Plain old ruby objects factory :url, class: String do skip_create protocol “http://” host “www.google.com” port 80 trait :secure do protocol “https://” end initialize_with { new(“#{protocol} #{host}:#{port}”) } end
21. Usage build(:url, :secure, host: “www.twitter.com”) # => “https://www.twitter.com:80
22. FactoryGirl resources • FactoryGirl Wiki - https://github.com/ thoughtbot/factory_girl/wiki • Thoughtbot Blog - https:// learn.thoughtbot.com/factory+girl/articles