These tests verify that the application will deliver to the users the value they are expecting. It is not just a matter of verifying the application meets its specifications, it is also about checking that specifications are correct. There is no application that is specified perfectly in advance.

Agile teams perform showcases to stakeholders the functionality during development and at the end of every iteration the functionality to be delivered, to ensure that any misunderstandings or specification problems are caught as early as possible. This causes to arise many improvements, stakeholders need to decide how much they want to take.

Acceptance / End to End

Recreates all the user flow. They are executed in a production-like environment. They can be developed with Cypress or Jest. We can get what they should do from the Definition of Done or Acceptance Criteria of our tasks. Another approximation is get the flow of a real user (through logs and events) and reproduce that behaviour in a controlled environment.

Acceptance tests are critical because they answer:

• "How do I know when I am done?" for developers
• "Did I get what I wanted?" for users

When both pass, requirement is completed.