Ruby on Rails Quality Control & Assurance 2

Question 1

Which RSpec matcher should you use to verify that a method raises a specific exception class?

Accepted Answer

expect { }.to raise_error(ErrorClass)

Answer

`raise_error` accepts an exception class and optionally a message to assert that a block raises that specific error.

Question 2

In Rails system tests using Capybara, what method waits for an element to appear before interacting with it?

Accepted Answer

find

Answer

Capybara's `find` method automatically waits up to the configured `default_max_wait_time` for an element to become present.

Question 3

Which tool is commonly used to measure Rails test coverage and identify untested code paths?

Accepted Answer

SimpleCov

Answer

SimpleCov is the standard Ruby gem that instruments code and reports line/branch coverage percentages after your test suite runs.

Question 4

What is the purpose of `VCR` gem in Rails testing?

Accepted Answer

Record and replay HTTP interactions to make tests deterministic

Answer

VCR records real HTTP interactions into cassette files and replays them in future test runs, eliminating external network calls.

Question 5

When using FactoryBot, what does `build_stubbed` do differently than `build`?

Accepted Answer

Creates an in-memory object with stubbed persistence methods without hitting the database

Answer

`build_stubbed` creates a fake-persisted object with a fake id, stubbing `persisted?` and `save` so no database interaction occurs.

Ruby on Rails Practice Test