What is state transition testing?

State transition testing is a black-box test design technique that focuses specifically on the different states that a system or application can be in, and how those states change based on various inputs or events. In this approach, testers identify the states of the application, the possible transitions between those states, and the conditions that trigger those transitions. By creating test cases that cover these transitions, testers can verify that the system behaves as expected when moving from one state to another.

This technique is particularly useful in scenarios where the system's behavior is dependent on its current state, which is common in event-driven software, user interfaces, and systems with complex workflows. For example, an application may have states like "logged out," "logged in," and "session expired," and the transitions would define how the application moves between these states based on user actions or system events.

The other options do not accurately describe state transition testing. Usability testing focuses on how user-friendly and accessible a product is, and while it can involve state observation, it does not involve transitions between different states. Testing software security primarily involves techniques aimed at identifying vulnerabilities and threats, which is unrelated to state management. Lastly, a structured approach to unit testing centers around testing individual components or units of code in isolation