Level of requirements

Requirement is a description of what functions and under what conditions an application has to perform.

5 key attributes of requirements testing

Completeness - check if all req. were covered with test scenarios (with all test cases).

(e.g.: “passwords must be encrypted” — what is the encryption algorithm?)

(e.g.: “export to PDF, PNG, etc.” — what does “etc.” mean here?)

(e.g., “the application should support the transfer of large amounts of data” — how much is “large”?

Up-to-date
Testability - there should be a way to check if implementation is correct or not

And overall requirement should be correct and truthful and make sense.

User story, acceptance criteria, priority has a set or characteristics to understand wether they all 3 are correct. So, what are the characteristics?

Functional = how the system must work, while non functional requirements explain how the system should perform (a behavior or function).

Use user stories to describe the functional requirements: As a <type of user>, I want <goal> so that <reason>”

Functional examples

Display the name, total size, available space and format of a flash drive connected to the USB port.” Other examples are “add customer” and “print invoice”.
Send email when a new customer signs up” or “Open a new account”.
Business Rules
Authentication
Authorization levels

Non functional examples

“must not break under pressure of less than 10,000 PSI”
“Modified data in a database should be updated for all users accessing it within 2 seconds.”
“contain hot liquid without heating up to more than 45°C”.
Performance – for example Response Time, Throughput, Utilization, Static Volumetric.
Availability
Fault tolerance
Recoverability
Security
Accessibility
Configuration
UI testing
Localisation and internationalisation

Difference

Usually easy to define, and Usually more difficult to define.

How to gather functional and non-functional requirements?