![Is The Software Defect Free ?
This principle arises from the
theory of the process of scientific ex testing
books. While you are not expected to read the scientific theory
[Popper] the analogy used in science is useful; however many white
swans we see, we cannot say 'All swans are white'. However, as soon
as we see one black swan we can say 'Not all swans are white'. In
the same way, however many tests we execute without finding a
bug, we have not shown 'There are no bugs'. As soon as we find a
bug, we have shown 'This code is not bug-free'.](https://image.slidesharecdn.com/fundamentaloftestingwhat-171211115625/85/Fundamental-of-testing-what-is-testing-13-320.jpg)
Fundamental of testing (what is testing)
- 1. Assalamua’laikum Wr.Wb CHAPTER 1 FUNDAMENTALS OF TESTING oleh: HELFA SAFITRI PRAGRAM STUDI S1 SISTEM INFORMASI FAKULTAS SAINS DAN TEKNOLOGI UNIVERSITAS ISLAM NEGERI SULTAN SYARIF KASIM RIAU Referensi : Graham et.al (2006) http://sif.uin-suska.ac.id http://fst.uin-suska.ac.id http://www.uin-suska.ac.id
- 2. What Is Testing ? Syllabus learning objectives for 1.2 What is testing? 1. Recall the common objectives of testing. (Kl) 2. Describe the purpose of testing in software development, maintenance and operations as a means to find defects, provide confidence and infor mation, and prevent defects. (K2) In this section, we will review the common objectives of testing. We'll explain how testing helps us to find defects, provide confidence and information, and prevent defects. We will also introduce additional fundamental principles of testing. As you read this section, you'll encounter the terms code, debugging,development of software, requirement, review, test basis, test case, testing and test objective.
- 3. The Driving Test - an Analogy For Software Testing Let's use an analogy to help us: driving tests. In a driving test, the examiner crit made by the driver under test. The examiner takes the driver through a route which tests many possible driving activities, such as road junctions of different types, control and maneuvering of the car, ability to stop safely in an emergency, and awareness of the road, other road users and hazards. Some of the activities must be tested. For example, in the UK, an emergency stop test is always carried out, with the examiner simulating the moment of emergency by hitting the dashboard at which point the driver must stop the car quickly, safely and without loss of control.
- 4. The Driving Test - an Analogy For Software Testing At the end of the test, the examiner makes a judgment about the driver'spe judgment on the number and severity of the failures identified, and also whether the driver has been able to meet the driving requirements. A single severe fault is enough to fail the whole test, but a small number of minor faults might still mean the test is passed. Many minor faults would reduce the confidence of the examiner in the quality —of the driving to the point where the driver cannot pass.
- 5. Defining Software Testing Let's break the definition down into parts; the definition has some key phrases remember. The definition starts with a description of testing as a process and then lists some objectives of the test process. This is a suitable definition of testing for any level of testing, from compo-nent testing through to acceptance testing, provided that we remember to take the varying objectives of these different levels of testing into account.
- 6. Software Test and Driving TestCompared We can see that the software test is very like a driving test in many ways, though of course it is not a perfect analogy! The driving examiner becomes the software tester. The driver being examined becomes the system or software under test, and you'll see as we go through this book that the same approach broadly holds. So, test activities exist before and after test execution. As a tester or test manager, you will be involved in planning and control of the testing, choosing test conditions, designing test cases based on those test conditions, executing them and checking results, evaluating whether enough testing has been done by Examining completion (or exit) criteria, reporting on the testing process and system under test, and presenting test completion (or summary) reports.
- 7. When Can We Meet Our Test Objectives ? We can use both dynamic testing and static testing as a means for achieving similar test objectives. Both provide information to improve both the system to be tested, and the development and testing processes. We mentioned above that testing can have different goals and objectives, which often include: Finding defects; Gaining confidence in and providing information about the level of quality; preventing defects.
- 8. Focusing On Defects Can Help Us Plan Our Tests Reviewing defects and failures in order to improve processes allows us to im processes. One phenomenon that many testers have observed is that defects tend to cluster. This can happen because an area of the code is particularly complex and tricky, or because changing software and other products tends to cause knock-on defects. Testers will often use this information when making their risk assessment for planning the tests, and will focus on known 'hot spots'.
- 9. Focusing On Defects Can Help Us Plan Our Tests A main focus of reviews and other static tests is to carry out testing as early as from appearing at later stages of this project. These activities help us find out about defects earlier and identify potential clusters. Additionally, an important outcome of all testing is information that assists in risk assess- ment; these reviews will contribute to the planning for the tests executed later in the software development life cycle. We might also carry out root cause analysis to prevent defects and failures happening again and perhaps to identify the cause of clusters and potential future clusters.
- 10. The Defect Clusters Change Over Time Over time, as we improve our whole software development life cycle and the defects. A typical test improvement initiative will initially find more defects as the testing improves and then, as the defect prevention kicks in, we see the defect numbers dropping. The first part of the improvement enables us to reduce failures in operation; later the improve-ments are making us more efficient and effective in producing the software with fewer defects in it.
- 11. The Defect Clusters Change Over Time As the 'hot spots' for bugs get cleaned up we need to move our focus else- where, to the next set of risks. Over time, our focus may change from finding coding bugs, to looking at the requirements and design documents for defects, and to looking for process improvements so that we prevent defects in the product.
- 12. Debugging Removes Defects When a test finds a defect that must be fixed, a programmer must do some rk to locate the defect in the code and make the fix. In this process, called debug-ging, a programmer will examine the code for the immediate cause of the problem, repair the code and check that the code now executes as expected. The fix is often then tested separately (e.g. by an independent tester) to confirm the fix. Notice that testing and debugging are different activities. Developers may test their own fixes, in which case the very tight cycle of identifying faults, debugging, and retesting is often loosely referred to as debugging. However, often following the debugging cycle the fixed code is tested independently both to retest the fix itself and to apply regression testing to the surrounding unchanged software.
- 13. Is The Software Defect Free ? This principle arises from the theory of the process of scientific ex testing books. While you are not expected to read the scientific theory [Popper] the analogy used in science is useful; however many white swans we see, we cannot say 'All swans are white'. However, as soon as we see one black swan we can say 'Not all swans are white'. In the same way, however many tests we execute without finding a bug, we have not shown 'There are no bugs'. As soon as we find a bug, we have shown 'This code is not bug-free'.
- 14. If We Don’t Find Defects Does That Mean The Users Will Accept The Software There is another important principle we must consider; the customers for soft-ware - the people and organizations who buy and use it to aid in their day-to-day tasks - are not interested in defects or numbers of defects, except when they are directly affected by the instability of the software. The people using soft-ware are more interested in the software supporting them in completing tasks efficiently and effectively. The software must meet their needs. It is for this reason that the requirements and design defects we discussed earlier are so important, and why reviews and inspections are such a funda-mental part of the entire test activity.