Test Case Generation from UML Models

Software Testing is one of the important phases in the software development life cycle. The cost of software testing is approximately 50% of the total development cost. In order to test software in an effective and an efficient manner, the test case should be generated systematically. Unified Modeling Language (UML) is the current industrial standard used to assist software development. It is widely used to describe the requirements and the design of the software in a number of diagrams. Each diagram provides a view of the system. The class diagram provides the static configuration, while the interaction diagrams describes the dynamics of the system behavior. This paper presents a methodology to generate the test case from a design level class diagram and an interaction diagram. It is in the category of model-based testing. It is assumed that the given model is correct and the goal of the testing is to check if the implementation conforms to the given model. A car rental example is used to illustrate the test case generation. The test adequacy criteria used in this paper are the coverage for the model elements, also called the building blocks in the class diagrams and the interaction diagrams. These criteria are based on the same premise for the underlying code testing criteria to help define testing objectives. The class diagram defines the object configuration and the interaction diagram determines the method sequence in the testing. The generated test cases are compared with a few other UML model-based test case generation methodologies; they are able to meet the required test adequacy criteria better.