Ruby on Rails Case Studies & Practical Application 4

Question 1

A Rails app's test suite takes 45 minutes to run. The biggest cost is database setup per test. Which strategy best reduces this?

Accepted Answer

Use database_cleaner with transaction strategy instead of truncation

Answer

The transaction strategy wraps each test in a rolled-back transaction, avoiding expensive truncation and dramatically cutting test time.

Question 2

You need to add full-text search to a Rails blog with PostgreSQL. What is the most pragmatic first choice?

Accepted Answer

Use pg_search gem leveraging PostgreSQL's built-in full-text search

Answer

pg_search uses PostgreSQL's native tsvector/tsquery, giving solid full-text search with no additional infrastructure.

Question 3

A Rails app must enforce that only admins can access the /admin namespace. Where is this best implemented?

Accepted Answer

Add a before_action in an AdminController base class that all admin controllers inherit from

Answer

A shared before_action in a base AdminController ensures the check runs for every admin action without duplicating code.

Question 4

A Rails app uses sessions to store shopping carts, but carts are lost when the session cookie expires. What is a better approach?

Accepted Answer

Store the cart in the database associated with the user or a guest token

Answer

Database-backed carts persist across sessions, devices, and expiry, and can be recovered after login.

Question 5

Your Rails app sends welcome emails after user registration. During a spike, the email queue backs up for hours. What is the correct scaling fix?

Accepted Answer

Add more Sidekiq workers or increase concurrency to clear the queue faster

Answer

Adding Sidekiq workers or increasing concurrency scales throughput to match the queue depth during traffic spikes.

Ruby on Rails Practice Test