NameError: uninitialized constant Faker

Question

I am trying to run a simple bundle exec rake db:seed for my database in Rails 4. However, when running it, I get the following output:

********-C02MGBVJFD57:myapp ***********$ bundle exec rake db:seed
Your Gemfile lists the gem factory_girl_rails (>= 0) more than once.
You should probably keep only one of them.
While it's not a problem now, it could cause errors if you change the version of just one of them later.
rake aborted!
NameError: uninitialized constant Faker
/Users/**********/workspace/myapp/db/seeds.rb:16:in `block in <top (required)>'
/Users/**********/workspace/myapp/db/seeds.rb:15:in `times'
/Users/**********/workspace/myapp/db/seeds.rb:15:in `<top (required)>'
/Users/**********/.rvm/gems/ruby-2.1.2@myapp/gems/railties-4.1.4/lib/rails/engine.rb:543:in `load_seed'
/Users/**********/.rvm/gems/ruby-2.1.2@myapp/gems/activerecord-4.1.4/lib/active_record/tasks/database_tasks.rb:184:in `load_seed'
/Users/**********/.rvm/gems/ruby-2.1.2@myapp/gems/activerecord-4.1.4/lib/active_record/railties/databases.rake:173:in `block (2 levels) in <top (required)>'
Tasks: TOP => db:seed
(See full trace by running task with --trace)

Here is my seeds.rb file:

User.create!(
  name:                  "Example User",
  email:                 "[email protected]",
  password:              "foobar",
  password_confirmation: "foobar",
  admin:                 true
)

99.times do |n|
  name     = Faker::Name.name
  email    = "example-#{n+1}@railstutorial.org"
  password = "password"
  User.create!(
    name:                  name,
    email:                 email,
    password:              password,
    password_confirmation: password
  )
end

Line 16 is:

name = Faker::Name.name

Any ideas why I am getting this error? Thank you.

Boatright

Do you have the faker gem? – Interfile

I have the faker gem under my gemfile in group :test do – Boatright

Were you running rake db:seed in the test environment? Assuming you are running it in development, you need to add it to your development group as well. – Interfile

ok that worked; sorry for the waste of time. – Boatright

It's not a waste of time if you learned something. Might be worthwhile to add your own answer at the bottom saying something like rake db:seed runs in the development environment. If you're using Faker in your seeds, make sure it's in both the development and test groups. – Verniavernice

Answer 1

Just faced similar issue - I was running

rails g model model_name

and getting the error:

uninitialized constant Faker (NameError)

Problem was due to fact, that I had gem added to test group.

Placing it into development and test group solved the problem:

group :development, :test do
  # ...
  gem 'faker'
  # ...
end

Breena

yup... :face_palm: – Brasil

Answer 2

I faced the same issue while writing rspec and adding require 'faker' in spec file solved it.

Mader

in the individual tests spec file or in the rails_helper.rb file? – Catboat

I had to use require 'faker' in rails console in development environment, thanks – Falkirk

Answer 3

I added gem 'faker' in the Gemfile. Then I run bundle install to get the gem.

Disesteem

As it’s currently written, your answer is unclear. Please edit to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers in the help center. – Bitt

Answer 4

As per official faker documentation, it said:

Note: if you are getting a uninitialized constant Faker::[some_class] error, your version of the gem is behind the one documented here. To make sure that your gem is the one documented here, change the line in your Gemfile to:

gem 'faker', :git => 'https://github.com/faker-ruby/faker.git', :branch => 'main'

But the problem still persist with mine app, since I have done this and I am getting the error again, but only when try to run the migrations to heroku:

heroku run rails db:migrate db:seed

When I run the command locally I do not have the problem and migrations and seeds are executed.

Encrust