We prepare ‘Software requirements and specifications’ document to define and specify user requirements. In the initial years of software development, requirement writers used to write stories to explain the expected behaviour of the system and its interactions with the external world. Ivar Jacobson and his team [JACO99] gave a new dimension and direction to this area and developed a Unified Modeling Language (UML) for software development. They introduced use case approach for requirements elicitation and modeling. This is a more formal way to write requirements. The customer knows what to expect, the developer understands what to code, the technical writer comprehends what to document and the tester gets what to test. The use cases address primarily the functional requirements, meaning thereby, the perspective of the users sitting outside the system. Use cases capture the expectations in terms of achieving goals and interactions of the users with the system.

The IEEE Std 830-1998 requires us to follow a systematic approach which may include the design of use cases, various forms for interaction with the user, data validations, reports, error handling and response to unexpected situations. This is an important document designed in the initial phases of the software development. In this chapter, techniques have been discussed to design test cases from requirements. Database testing has also been introduced to design test cases using interface forms.

USE CASE DIAGRAM AND USE CASES

Use case diagram is also used along with use cases to explain the functionality of the system. This is a graphical representation and gives the top view of the system along with its users and use cases. Use case diagram may be decomposed into a further level of abstraction. Use cases and use case diagrams are normally used together to define the behaviour of a system.