Testability of Software Systems

Software testing is one of the most expensive phase of the software development life cycle. Testing object oriented software is more expensive due to various features like abstraction, inheritance etc. The cost of testing can be reduced by improving the software testability. Software testability of a class is generally measured in terms of the testing effort which is equal to the number of test cases required to test a class. Hence testability can be improved if the test cases can be reduced. Software contracts (method preconditions, method postcondtions, and class invariant) can be used in improving the testability of the software. The paper provides some suggestions that will inspire teams to make their software products more testable. It cites examples of testability features that have been used in testing various software products, it also provides a detailed exploration of how testability issues affect GUI test automation and what kinds of provisions testers must make when testability is lacking.