FactoryGirl + Faker - same data being generated fo

问题:

I am using FactoryGirl and Faker to generate user objects in my seeds.rb file but for some reason the exact same user is being created and rake db:seed is failing because of an email uniqueness validation.

Factory for users:

#users.rb
require 'faker'

FactoryGirl.define do
  factory :user do
    first_name            Faker::Name.first_name
    last_name             Faker::Name.last_name
    phone                 Faker::PhoneNumber.cell_phone
    email                 Faker::Internet.email
    password              "password"
    password_confirmation "password"
  end
end

And the code in seeds.rb file:

#seeds.rb
rand(5..11).times { FactoryGirl.create(:user) }

Error:

ActiveRecord::RecordInvalid: Validation failed: Email has already been taken

If I open the console and use FactoryGirl.create(:user) I get the same results...same object is being created over and over even though if I run just Faker::Internet.email several times I'll get several e-mails.

FactoryGirl:

[1] pry(main)> FactoryGirl.create(:user)
...
=> #<User id: 3, first_name: "Osvaldo", last_name: "Wunsch", email: "[e-mail]", phone: "[phone] x64848", created_at: "2014-07-31 20:57:27", updated_at: "2014-07-31 20:57:27", encrypted_password: "$2a$10$mxWC7yLYR0m/Sw8MO6Lyru.xuTHCdCEuM9Orx3LXGApF...", reset_password_token: nil, reset_password_sent_at: nil, remember_created_at: nil, sign_in_count: 0, current_sign_in_at: nil, last_sign_in_at: nil, current_sign_in_ip: nil, last_sign_in_ip: nil>
[2] pry(main)> FactoryGirl.create(:user)
...
ActiveRecord::RecordInvalid: Validation failed: Email has already been taken

Faker by itself:

[3] pry(main)> Faker::Internet.email
=> "[e-mail]"
[4] pry(main)> Faker::Internet.email
=> "[e-mail]"

What am I missing here? Why is Faker producing the same data every time when used through FactoryGirl?

回答1:

You need to pass a block if you want the values re-evaluated for each instance created.

Instead of

email   Faker::Internet.email

try...

email   { Faker::Internet.email }

回答2:

Using Faker to get uniqueness-passing attributes may be an anti-pattern. It may also be a bad idea to have Faker's semi-random output in tests - what if sometimes tests just fail and you are off to a wild goose chase just because Faker coughed up a value you did not expect?

Lately I have been using FactoryGirl's sequences to get predictable, yet uniqueness-passing values.

FactoryGirl.define do
  factory :user do
    sequence(:first_name, 1) { |n| "John#{n}" }
    sequence(:last_name, 1) { |n| "Doe#{n}" }
    sequence(:phone, 1) { |n| (111111111+n).to_s }               
    sequence(:email, 1) { |n| "email#{n}@example.com" }        
    password              "password"
    password_confirmation "password"
  end
end

FactoryGirl.create(:user).email #=> "[e-mail]"
FactoryGirl.create(:user).email #=> "[e-mail]"

Taken from Factory Girl tips @ http://arjanvandergaag.nl/blog/factory_girl_tips.html