Application testing is a process involved in all life cycles of software development. It implies review and planning of the product requirements, preparation and performance of changes. As a result testers reveal inadequacies and errors. And trying to get a systematic view, every person in software development company actually plays the role of tester. If you look at IT-project as at a person, then roles of different specialists can be described in the following way:
- Project Manager is a backbone and the autonomic nervous system
- Programmers are a skeleton and motor nerves
- Analysts are organs of sense
- Testers is conscience
Software Quality Assurance is often considered as a synonym of testing, but this method actually was called upon to prevent errors beforehand, rather than finding and fixing them. Quality in this sense should be considered as a characteristic of finished product (software or web-application).
So, testers have to verify even requirements specifications, project plans and analysis, not just program code and interface. Software testing is particularly important in critical systems.
For example, the Therac Radiotherapy apparatus (1985) irradiated 6 people with lethal dose of radiation due to the lack of code verification and validation. Or Mars exploration rover (1999) brought the loss of 125 million dollars because of crude common measurement system between developers.
And even during the electronic elections in Estonia there were some problems because of poor high-load testing. These examples and practice of software and web development companies shows that all testers should follow basic principles from ISTQB test documentation and other sources.