FactoryBot::Sorbet

TODO: Delete this and the text below, and describe your gem

Welcome to your new gem! In this directory, you'll find the files you need to be able to package up your Ruby library into a gem. Put your Ruby code in the file lib/factory_bot/sorbet. To experiment with that code, run bin/console for an interactive prompt.

Installation

Install the gem and add to the application's Gemfile by executing:

bundle add factory_bot-sorbet

If bundler is not being used to manage dependencies, install the gem by executing:

gem install factory_bot-sorbet

Usage

This gems adds the module FactoryBot::Sorbet which contains methods for using all your factories in a type-safe way.

The problem

Given a factory

FactoryBot.define do
  factory :foo, class_name: "Foo" do
    bar { "BAR!" }
  end
end

Using regular FactoryBot you'd use it like so:

FactoryBot.create(:foo, baz: 1) #=> #<Foo:0x0000000106021fc8 @bar="BAR!" @baz=1>
FactoryBot.build(:foo, baz: 2) #=> #<Foo:0x0000000106021fc8 @bar="BAR!" @baz=2>
FactoryBot.build_stubbed(:foo, baz: 3) #=> #<Foo:0x0000000106021fc8 @bar="BAR!" @baz=3>

This DSL has one problem when used with sorbet. It is impossible to create a static signature for create, build, build_stubbed because they return a different type each time based on the first argument.

The solution

This gem defines unique methods for each factory and defines static sorbet signatures for them using a Tapioca compiler.

FactoryBot::Sorbet.foo(:create, baz: 1) #=> #<Foo:0x0000000106021fc8 @bar="BAR!" @baz=1>
FactoryBot::Sorbet.foo(:build, baz: 2) #=> #<Foo:0x0000000106021fc8 @bar="BAR!" @baz=2>
FactoryBot::Sorbet.foo(:build_stubbed, baz: 3) #=> #<Foo:0x0000000106021fc8 @bar="BAR!" @baz=3>

Tapioca will generate the following RBI file to make Sorbet fully understand the types of your factories.

# sorbet/rbi/dsl/factory_bot/sorbet.rbi

# typed: true

# DO NOT EDIT MANUALLY
# This is an autogenerated file for dynamic methods in `FactoryBot::Sorbet`.
# Please instead update this file by running `bin/tapioca dsl FactoryBot::Sorbet`.


module FactoryBot::Sorbet
  sig { params(strategy: Symbol, args: T.anything, block: NilClass).returns(Foo) }
  sig do
    type_parameters(:R)
      .params(
        strategy: Symbol,
        args: T.anything,
        block: T.proc.params(arg0: Foo).returns(T.type_parameter(:R))
      ).returns(T.type_parameter(:R))
  end
  def foo(strategy, *args, &block); end
end

Test Helpers

If you use Rails/Minitest (or any other test framework) we highly recommend adding a helper methods for easier access to your factories.

# test/test_helper.rb

require 'factory_bot/sorbet'

class Minitest::Test
  include FactoryBot::Sorbet::TestHelpers
end

This will the let you use the shorthand:

f.foo(:create)

Instead of:

FactoryBot::Sorbet.foo(:create)

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/Verseth/ruby-factory_bot-sorbet.