Object-oriented software testing Paulius Urbonas IFM-0/2 2011-05-11

Theme overview Object-oriented software testing purposes Different testing levels Testing methods Benefits of object-oriented software testing Object-oriented software testing issues

The purposes of object-oriented software testing It is used for testing object-oriented systems. It is necessary for testing system objects interactions and behavior in various situations. It tests interfaces of the system components that are put together.

Object-oriented software testing levels Testing an object Testing sets of objects Testing an entire system

Testing an object (unit testing) Unit is a smallest component that can be compiled and executed. There are two options for selecting single unit in object- oriented software: treat each class as unit; treat each method within a class as unit. Unit is normally a component which is only assigned to one programmer.

Single unit testing in object-oriented software Smallest testable unit is the encapsulated class. Test each operation as part of a class. Identify all object attributes. Test all object states behavior. Inheritance leads to a lot of difficulty for testing classes, because of lack of information localization.

Testing sets of objects (integration testing) Integration testing is the testing of the interaction between two or more object-oriented components by sending a message. Integration testing assumes that unit testing has been done on the components and defects have been removed. The goal of integration testing is to find defects that arise when object-oriented components interact with each other in an incorrect way.

Testing an entire system Black box testing Creating test cases by using user requirements or specifications. White box testing Creating test cases by using software code.

Use cases testing Random testing Partitioning testing Testing methods Use cases testing Random testing Partitioning testing

Use cases testing Based on use cases. Focus on user interaction, but not on system interaction. Describes a specific user needs.

Random testing Identify operations applicable to a class. Define constraints on operations use. Identify a minimum test sequence. Generate a variety of random valid test sequences.

Partitioning testing State-based partitioning: Categorize and test operations based on their ability to change the state of a class. Attribute-based partitioning: Categorize and test operations based on the attributes that they use. Category-based partitioning: Categorize and test operations based on the generic function each performs (state changing, queries, termination).

Object-oriented software testing benefits Allows to test individual software objects and their interaction. Allows to detect errors in the initial phase of system implementation. Allows easily automated testing with special tools.

Object-oriented software testing problems Integration testing may add a large cost (time resources) to software development process. Polymorphism - attribute may have more than one set of values and an operation may be implemented by more than one method. Inheritance - object may have more than one super class. Encapsulation - information hiding.

Questions Object-oriented software testing levels? Benefits of object-oriented software testing? Drawbacks of object-oriented software testing?