User Stories are part of business analysis. User stories are usually used in prototyping the system, but can be a powerful input in test analysis. They can help a test analyst imagine how the target system will be used. A test analyst can write test cases according to user stories.
Given the following overarching purpose (mission statement) for an application: In order to help keep a healthy and refreshing sleep regime, or in order to limit computer-related addictive behaviors, ...