Elevating Your Code Quality: Bullet Gem and N+1 Query Prevention in Testing

Rodrigo Assis
November 29, 2023

In the world of Ruby on Rails development, identifying and resolving N+1 query issues is crucial for maintaining efficient and performant applications. N+1 queries are a notorious bottleneck that can impact application speed.

In this blog post, we’ll integrate the Bullet gem into your test environment to have real-time feedback on N+1 query issues.

Understanding N+1 Queries:

N+1 queries arise when fetching a collection of records leads to an additional query for each individual record. This can cause a cascade of queries, slowing down your application’s responsiveness. While identifying and fixing N+1 queries during development is crucial, it’s equally important to catch these issues early in your test suite.

The Role of Bullet Gem:

The Bullet gem serves as a vigilant guardian against N+1 query pitfalls. By integrating it into your test environment, you empower yourself to catch these issues as part of your testing process. Bullet acts as an assertive assistant, notifying you whenever N+1 queries are detected during test runs, ensuring your codebase remains performant and resilient against potential bottlenecks.

Setting Up Bullet in Your Test Environment:

1. Gem Installation:

Begin by adding the Bullet gem to your Gemfile:

group :development, :test do
  gem 'bullet'

2. Configuration:

Configure Bullet to operate in your test environment by enabling it in your config/environments/test.rb

config.after_initialize do
  Bullet.enable        = true
  Bullet.bullet_logger = true
  Bullet.raise         = true # raise an error if n+1 query occurs

Also in your spec/rails_helper.rb

if Bullet.enable?
  config.before(:each) do

  config.after(:each) do
    Bullet.perform_out_of_channel_notifications if Bullet.notification?

Preventing and Fixing N+1 Queries in Tests:

1. Proactive Prevention:

As you write code and run your tests, Bullet will immediately notify you if N+1 query issues are introduced. This real-time feedback enables you to proactively address and prevent these problems during the development phase.

2. Rapid Issue Resolution:

Bullet not only prevents N+1 issues but also aids in their swift resolution. The gem provides detailed feedback about the problematic queries, guiding you to optimize associations through eager loading or adding includes.


By embracing the Bullet gem within your test environment, you become a more proficient developer. The ability to identify and rectify N+1 queries during the testing phase not only fortifies your code against performance bottlenecks but also cultivates a development mindset focused on efficiency and code quality.

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