RSpec expectations define expected outcomes
A diff is the part of a failure message showing the differences between data structures
Domain-Driven Design relies on business requirements
How to start with DDD when you have a monolith - Javiera Laso (DDD Europe 2022)
BDD is a testing philosophy that grew out of test-driven development (TDD). Essentially, the goal of both is: write tests first, then write code to make the tests pass! — Isa Levine
Collaborative Software Design, Gien Verschatse (DDD Europe 2023)
Crafting Domain-Driven Designed REST APIs, Julien Topçu (DDD Europe 2022)