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FactoryBot relies on ruby >= 2.5, so we can use Regexp#match? that does not allocate MatchData

Allocations measured with heap-profiler gem in an internal test suite with 7497 examples and 149470 calls to aliases_for:

allocated memory by file
    59.79 MB  factory_bot-6.1.0/lib/factory_bot/aliases.rb
    38.27 MB  factory_bot-6.1.0/lib/factory_bot/aliases.rb

allocated objects by file
    896880  factory_bot-6.1.0/lib/factory_bot/aliases.rb
    597940  factory_bot-6.1.0/lib/factory_bot/aliases.rb

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Jun 10, 2020

factory_bot Build Status Code Climate Gem Version

factory_bot is a fixtures replacement with a straightforward definition syntax, support for multiple build strategies (saved instances, unsaved instances, attribute hashes, and stubbed objects), and support for multiple factories for the same class (user, admin_user, and so on), including factory inheritance.

If you want to use factory_bot with Rails, see factory_bot_rails.

Interested in the history of the project name?

Transitioning from factory_girl?

Check out the guide.


You should find the documentation for your version of factory_bot on Rubygems.

See GETTING_STARTED for information on defining and using factories. We also have a detailed introductory video, available for free on Upcase.


Add the following line to Gemfile:

gem 'factory_bot'

and run bundle install from your shell.

To install the gem manually from your shell, run:

gem install factory_bot

Supported Ruby versions

Supported Ruby versions are listed in .github/workflows/build.yml

More Information

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factory_bot was originally written by Joe Ferris and is maintained by thoughtbot. Many improvements and bugfixes were contributed by the open source community.


factory_bot is Copyright © 2008-2020 Joe Ferris and thoughtbot. It is free software, and may be redistributed under the terms specified in the LICENSE file.

About thoughtbot


factory_bot is maintained and funded by thoughtbot, inc. The names and logos for thoughtbot are trademarks of thoughtbot, inc.

We love open source software! See our other projects or hire us to design, develop, and grow your product.