1 Testing Aspect-Oriented Programs with UML Design Models

The new constructs in aspect-oriented programming bring new types of programming faults with respect to crosscutting concerns, such as incorrect pointcuts and advice. This paper presents a UML-based approach to testing whether or not an aspect-oriented program conforms to its expected crosscutting behavior. We explore aspect-oriented UML design models to derive tests for exercising interactions between aspects and classes. Each aspect-oriented model consists of class diagrams, aspect diagrams, and sequence diagrams. For a method under test, we weave the sequence diagrams of the advice on the method into the method’s sequence diagram. Based on the woven sequence diagram and class/aspect diagrams, we then generate an AOF (Aspect-Object Flow) tree by applying coverage criteria such as condition coverage, polymorphic coverage, and loop coverage to woven sequence diagrams. In the AOF tree, each path from the root to a leaf is an abstract message sequence, indicating a template of test cases. A concrete test case is obtained by creating objects that satisfy the collective constraints in the template. Our empirical study shows that the model-based testing approach is capable of revealing several types of aspect-specific faults, including incorrect advice type, incorrect (weaker or stronger) pointcut strengths, and incorrect aspect precedence