The Future of Testing Chapter 21

Random testing Simply put, if testing is targeted at a particular area, it is because that area is either critical, or it is suspected that defects are in that area. In either case, inspection should be carried out! If nothing warrants inspection, then perhaps the tests should be ‘random’. That is, perhaps they should be applied at random across the entire system.

User profile ● Many times, testing can be based on what the user is likely to do with the system. ● The idea of usage profiling is to determine which parts of the system will get the heaviest use, and focus testing more on the high-use functions and less on the least-used functions.

Random input values ● Random input values approach would allow testers to generate input values based on a “random input generator”, the check the outputs based on what the specification says should appear. ● Distribution of the random input values can be filtered through a “profile”, if necessary, but then loses it’s true “randomness.”

Reliability Reliability is often uses as a “fuzzy” term for a measure of defect frequency. In fact, reliability has an actual formal definition: R = (1 – f ) k Where R is reliability, f is the failure probability (in failures/demand) for k executions of the software.

Automated Testing ● Automated testing can fall into two areas: automated application of tests and automatic test generation. ● Automatic test generation uses a formal representation of the specification to build test script that can be applied by a test harness to the system under test.

Regression Testing Regression testing uses a knowledge of what has been changed in the system to limit the scope of testing so that the entire test suite doesn’t ‘need’ to be applied. Regression tests are selected on the basis of what the ‘scope of effect’ is for changes to the system. If a change can effect another subsystem that has not be modified, should that subsystem be tested also?

State of the Software Testing Art ● Software testing is still a young ‘science’. There are many areas where ambitious researchers (and engineers) can still make significant contributions to the discipline. ● Many questions still remained unanswered in the areas of effectiveness, economics of testing and approaches.