Why are acceptance criteria developed?

Acceptance criteria are developed to define what constitutes "correctly functioning" functionality or system from the perspective of the business owner or user. They serve the following purposes:

1. Clear requirement definition: Translating general user stories or specifications into specific, testable conditions.
2. Alignment with stakeholders: Ensuring a common understanding of the expected behavior among customers, developers, testers, and other project participants.
3. Basis for testing: Providing explicit scenarios and expected results used for planning, development, and execution of tests.
4. Definition of Done: Part of the criteria that determine when functionality is considered complete and ready for release.
5. Reducing uncertainty and risks: Minimizing the likelihood of misunderstandings that could lead to errors and rework.

Typically, acceptance criteria are written in the "Given-When-Then" format or using a list of conditions.

// Example of acceptance criteria for a user story:
// As a registered user, I want to see my orders to track their status.

Scenario: Viewing the list of orders
  Given I am logged in as a registered user
  And I have completed orders
  When I navigate to the "My Orders" page
  Then I see a list of my orders
  And each order displays a number
  And each order displays a date
  And each order displays a status
  And each order displays a total amount