ruby-testing

Use RSpec.describe blocks with describe, context, and it for behavior organization, and expect syntax for assertions. The skill generates specs following AAA structure with let and subject for lazy setup, runnable via bundle exec rspec.

Use instance_double with allow and expect to stub or verify calls at service boundaries. For HTTP interactions, record real responses with VCR cassettes instead of hand-written stubs, and enable verify_partial_doubles in spec_helper.

RSpec offers BDD-style describe/it syntax, rich matchers, and built-in mocking, making it the dominant choice for Rails apps. Minitest is Ruby's built-in framework, simpler and faster, suited for smaller projects or minimal dependencies.

Flakiness usually comes from database state leakage, time dependence, or test ordering. Use DatabaseCleaner with truncation, Timecop or travel_to for time freezing, and run with --order random plus --seed to reproduce failures.

Avoid it for general Ruby feature implementation without test context, gem or bundler issues, and Ruby version management. It also stops and asks when no test framework exists, dependencies are missing, or tests would need production credentials.