NameError: uninitialized constant Faker - ruby-on-rails

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: "example#railstutorial.org",
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.

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

Answer 2

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

Answer 3

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

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.