FixtureKit

Fixture-level performance without giving up FactoryBot-style test setup.

Rails fixtures are very performant. But in large companies with hundreds of models and varying Rails familiarity, maintaining a well-manicured garden of YAML files quickly becomes unrealistic.

Teams reach for tools like FactoryBot to simplify test setup and keep things readable. The tradeoff is performance. FixtureKit gives you the speed wins while letting you keep the test setup tooling your teams already use, by generating and caching fixture data on-demand.

• Full documentation (guides): GitHub Wiki
• API/reference (canonical): docs/reference.md

Installation

group :test do
  gem "fixture_kit"
end

Quick Start

1. Define a fixture

# spec/fixture_kit/project_management.rb
FixtureKit.define do
  owner = User.create!(name: "Alice", email: "[email protected]")
  project = Project.create!(name: "Roadmap", owner: owner)

  expose(owner: owner, project: project)
end

2. Configure your framework

RSpec:

# spec/rails_helper.rb
require "fixture_kit/rspec"

RSpec.configure do |config|
  config.use_transactional_fixtures = true
end

Minitest:

# test/test_helper.rb
require "fixture_kit/minitest"

class ActiveSupport::TestCase
  self.use_transactional_tests = true
end

3. Use the fixture in tests

RSpec:

RSpec.describe Project do
  fixture "project_management"

  it "loads exposed records" do
    expect(fixture.project.owner).to eq(fixture.owner)
  end
end

Minitest:

class ProjectTest < ActiveSupport::TestCase
  fixture "project_management"

  test "loads exposed records" do
    assert_equal fixture.owner, fixture.project.owner
  end
end

fixture returns a Repository, and exposed names become reader methods.

Requirements

• Ruby >= 3.3
• ActiveRecord >= 8.0
• ActiveSupport >= 8.0

Releasing

1. Bump the version in lib/fixture_kit/version.rb
2. Update lockfiles:

   bundle install
   cd spec/dummy && bundle install && cd ../..
   bundle exec appraisal install
   

3. Commit and push to main:

   git add lib/fixture_kit/version.rb spec/dummy/Gemfile.lock gemfiles/*.gemfile.lock
   git commit -m "Release vX.Y.Z"
   git push
   

4. Create a GitHub release:

   gh release create vX.Y.Z --title "vX.Y.Z" --target main --generate-notes
   

License

MIT. See LICENSE.