Saturday, December 5, 2009

Why should we test our software?

This article is not only for testers, but also managers interested in what software testing could bring for them and perhaps does not bring now. Therefore I start with definitions of two terms, which I often use here:

Quality Assurance - planned and systematic processes designed to ensure the suitability of the product for its intended purpose.

Testing - the process of collecting and sorting information obtained through the examination of the product, a part of more general quality assurance.

If we feel that the testing and quality assurance is not given enough attention, and this side of the software development is constantly underestimated, perhaps we are not able to convince others of the importance of testing and its expert management.

So what are the benefits of software testing and quality assurance? Which items should we mention in the presentation of its benefits?

Quality assurance process affects three managerially important areas:
- Marketing
- Risk management
- Reducing costs


The fact that a good product delivered to a customer has a positive impact on reputation of company, while highly unreliable software destroys its reputation, is a simple logical conclusion. It is harder to predict or just realize a level of this influence. Poor product influences reputation in waves, some of them are immediate and fast disappearing, some has negative impact on business for several years.

The first wave is a response of direct customer, who makes decisions about subsequent cooperation based on his contentment.

The second wave is the reaction of end customers. They can cause a number of inconveniences in the case of bad reception of a product. Their constant complaints and bug reporting can cause project to go unexpectedly overprice. So that initially profitable project can become unprofitable project. Furthermore, their negative reception of a product may cause a change in the view of management on the supplier or get among the general public through newspaper and television news.

The third wave is a reaction of current employees and others in the field of software development. Reputations of software companies spread further due to constant staff turnover and persist for many years. Competent employees leave firms that are not able to deliver software in required quality because they do not want to be associated with next failure, or because they are simply not motivated to improve there. Where is no objective criteria of quality there is always a lack of efforts to improve. For the same reasons, good potential employees avoid the firm. They heard negative things about it from former or current employees.

The fourth wave, which affects a software company with the largest delay, is the reluctance of other customers or other software firms to cooperate with it. It is not possible to conceal a lack of efforts to ensure quality and poor processes from employees. If these employees are convinced that they themselves would never give their firm a contract for software development, then they would be less willing to give this company a contract even after several years when they will make such decisions from a position of managers and directors. The same goes for anyone who learned about poorly designed processes from their colleagues and friends.

In these four waves, each project influences according to its quality and impact in a positive or negative direction the company's business.

Risk management

Testing is a tool to obtain objective information on the status of developed software. This information is the most important input for risk management of software development. Testing is intertwined through the entire process of development. From the very beginning, testing controls compliance of the development with customer's needs, clarity and logic of outputs. It prevents misunderstandings and unnecessary waste of resources by timely informing about the shortcomings and errors. Quality assurance moreover define procedures and monitors developments in terms of providing simplicity, clarity, accuracy, precision, speed and other quality standards. As a result there is both a significant reduction in the likelihood of quality problems during and after development, and a limitation of an impact when a problem occurs.

Testing significantly prevents problems with malicious bugs. A single malicious bug in financial, medical or other critical sector can impact a loss that exceeds the entire budget for the development of this software.

Without testing, there are only two unpleasant ways to reduce the risk associated with software development:
- To find the subcontractor that takes a responsibility to some extent
- If it is possible, to insure against certain types of problems

Reducing costs

Although one of the most common management mistakes is sacrificing the quality during cost reduction, it is just effective quality assurance that brings the greatest savings. From the economic point of view, testing should last as long as the estimated average cost of finding and correcting a bug discovered in the next test cycle is less than the average cost of a bug discovered by the customer multiplied by the probability of its discovery. Simply, testing should last as long as it is financially more profitable than not testing. Quality assurance is an investment, so it is useful to monitor its return.

The problem is that it is very difficult to manage quality management with maximum efficiency and minimum cost. Such a task requires experience, feeling and excellent knowledge of a professional. Therefore, when you assure quality, you need to do well.

How to start?

Set effective testing process is not a one time thing, but it is created by constant tuning based on different reasonably chosen metrics which warn unless everything is alright and where you can monitor the deterioration or improve efficiency.

Understanding the key role of quality management in software development, setting standards, quality control process and having excellent professionals with experience directly in testing is a good basis for any quality assurance department.


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