What is FactoryBot?

FactoryBot is a Ruby library for setting up test data efficiently. Instead of manually creating test records in each test case, FactoryBot provides a factory-based approach to generate test data dynamically.

Why Use FactoryBot?

• Reduces repetitive code when creating test data.
• Ensures test objects are structured correctly.
• Makes tests more readable and maintainable.
• Provides flexibility for generating variations of test data.

Installation & Setup

• FactoryBot is already included in the Gemfile under the development and test groups:

  group :development, :test do
    gem "factory_bot_rails"
  end
  

• Run bundle install to install the gem.

• To enable FactoryBot syntax shortcuts, it has been configured in spec/rails_helper.rb:

  RSpec.configure do |config|
    config.include FactoryBot::Syntax::Methods
  end
  

  This allows you to write create(:expense) instead of FactoryBot.create(:expense).

Factory Directory & File Structure

FactoryBot stores factory definitions in the spec/factories directory.

• spec/factories/expenses.rb: Defines how an Expense object should be generated for tests.
• Other models will have their respective factory files inside spec/factories.

Example: Expense Factory

A factory for the Expense model has already been created:

FactoryBot.define do
  factory :expense do
    name { "Internet Bill" }
    amount { 69.00 }
    date { Date.new(2025, 1, 31) }
    category { "Utilities" }
  end
end

This allows for easy test data creation:

let(:expense) { create(:expense) } # Creates a valid Expense object

How to Use FactoryBot in Tests

• Creating a single record:

expense = create(:expense)

• Creating multiple records:

expenses = create_list(:expense, 5)

Troubleshooting Common Issues

• Issue: uninitialized constant FactoryBot
  • Ensure factory_bot_rails is installed and included in the test environment.
• Issue: undefined method create
• Make sure config.include FactoryBot::Syntax::Methods is present in rails_helper.rb.