Explore test-driven development (TDD) in Spring applications with this comprehensive conference talk from Spring I/O 2019. Discover how TDD empowers developers to build with confidence, enabling rapid delivery of production-ready code. Learn techniques for testing basic components, utilizing mocks, leveraging test slices, and validating web applications. Dive into consumer-driven contract testing (CDCT) to ensure seamless integration between API producers and consumers without compromising the testing pyramid. Follow along as Spring Developer Advocate Josh Long demonstrates practical examples, covering topics such as reactive Spring, testable code structure, persistence testing, HTTP endpoint validation, configuration testing, web client implementation, and wire mocking.