Slice Based testing and Object Oriented Testing

Editor's Notes

• #2 Where are these notes visible??
• #5 Program slices are more manageable for testing and debugging rather than taking up whole code. • During testing, debugging, or understanding a program, most of the code in the program is irrelevant to what you are interested in. • Program slicing provides a convenient way of filtering out “irrelevant” code.
• #6 Slicing criterion may include: Slicing variable: Slicing variable may be based on the variables specified in the criteria (slicing point of interest) or it may be on all variables. Type of the result: The result of slicing may be equivalent to the program of few set of statements from the program. Slicing Point: Considering the Slicing point, programmer interest may be before or after a particular statement [4]. Scope: The scope of the slice may be interprocedural or it may be intraprocedural [30]. Slicing Direction: The expected slice from the program may be in the forward or backward direction. Type of Information: The information that we obtain from the slice will be either a static or it may be a dynamic one. Output format: The format that can be obtained after slicing may seem to be in the form of code which is equivalent to source code or it may be a dependence graph or may be in the form of execution tree.
• #8 A static slice of a program contains all statements that may affect the value of a variable at any point for any arbitrary execution of the program. Static slices are generally larger. It considers every possible execution of the program.
• #10 A dynamic slice of a program contains all the statements that actually affect the value of a variable at any point for a particular execution of the program. Dynamic slices are generally smaller. Considers only a particular execution of the program.
• #12 static slice takes all the possible execution (in this case it is 2) of the program which may affect the value of the variable sum. Whereas in case of dynamic slicing, it considers only a particular execution (when n = 22) of the program which may affect the value of the variable sum.
• #13 Whenever large scale systems are designed, object oriented testing is done rather than the conventional testing as the concepts of object oriented programming is way easy than conventional ones.  this testing revolves around the fundamental entity known as “class”.  With this ,the larger systems are divided into small units which may then be implemented separately.
• #14 We are aware of OOP that it is a particular way of programming that leverage the concept of Classes and Objects and the 4 paradigms of Object Oriented Programming that are Abstraction: a process where you show only “relevant” data and “hide” unnecessary details of an object from the user. Encapsulation: a practice that bind the data with the code that manipulates it and keeps the data and the code safe from external interference Inheritance: the mechanism by which an object acquires the some (or all) properties of another object. Polymorphism: a way to process objects differently based on their data type. In other words objects can have the same name for a method but the implementation may differ.
• #15 Class testing ensures that the attributes of class are implemented as per the design and specifications. Also, it checks whether the interfaces and methods are error free of not. - System testing: the system is tested as whole and primarily functional testing techniques are used to test the system. Non- functional requirements like performance, reliability, usability and test-ability are also tested.
• #17 Identify each test case uniquely - Associate test case explicitly with the class and/or method to be tested State the purpose of the test Each test case should contain: A list of messages and operations that will be exercised as a consequence of the test A list of exceptions that may occur as the object is tested A list of external conditions for setup (i.e., changes in the environment external to the software that must exist in order to properly conduct the test) Supplementary information that will aid in understanding or implementing the test Automated unit testing tools facilitate these requirements
• #18 the dependencies occurring in conventional systems are: Data dependencies between variables Calling dependencies between modules Functional dependencies between a module and the variable it computes Definitional dependencies between a variable and its types. But in Object-Oriented systems there are following additional dependencies: Class to class dependencies Class to method dependencies Class to message dependencies Class to variable dependencies Method to variable dependencies Method to message dependencies Method to method dependencies 2. it is not possible to test the class dynamically, only its instances i.e, objects can be tested. 3. the concept of inheritance opens various issues e.g., if changes are made to a parent class or superclass, in a larger system of a class it will be difficult to test subclasses individually and isolate the error to one class. Test cases designed for base class are not applicable to derived class. 4. Encapsulation of attributes and methods in class may create obstacles while testing. As methods are invoked through the object of corresponding class, testing cannot be accomplished without object. 5. In addition, the state of object at the time of invocation of method affects its behavior. Hence, testing depends not only on the object but on the state of object also, which is very difficult to acquire.