Consider the following user story: As a student, I want to be able to buy...

The acceptance criteria are the conditions that must be met for the user story to be considered done and acceptable by the user. They should be defined and testable, meaning that they are clear, measurable, and verifiable. The acceptance criteria for the user story are not well-defined and testable, because they do not specify how the payment is made, how the registration is verified, andhow the monthly limit is enforced. These details are important for testing the functionality and quality of the user story, and should be included in the acceptance criteria. References = ISTQB Certified Tester Advanced Level Syllabus Test Analyst, Section 2.2.1, Use Case Testing1; How to Write a Good User Story, Section Acceptance Criteria2; Test User Stories with these 10 Tests, Section Testable3