Hast mentioned that they trust their unit tests and integration tests individually, and all of them together as a whole. They have no end-to-end tests: We achieved this by using good separation of concerns, modularity, abstraction, low coupling, and high cohesion. These mechanisms go hand in hand with TDD and pair programming. The result is a better domain-driven design with high code quality. Previously, they had more HTTP application integration tests that tested the whole app, but they have moved away from this (or just have some happy cases) to more focused tests that have shorter feedback loops, Hast mentioned.
Agile frameworks like Scrum or SAFe help teams rapidly validate ideas with end users. Meanwhile, DevOps practices ensure that validated ideas move safely and quickly through build, test and deployment pipelines.
