A common perception of testing is that it only consists of running tests, i.e. executing the software. This is part of testing, but not all of the testing activities. Test activities exist before and after test execution: activities such as planning and control, choosing test conditions, designing test cases and checking results, evaluating exit criteria, reporting on the testing process and system under test, and finalizing or closure (e.g. after a test phase has been completed). Testing also includes reviewing of documents (including source code) and static analysis.
Both dynamic testing and static testing can be used as a means for achieving similar objectives, and will provide information in order to improve both the system to be tested, and the development and testing processes.
There can be different test objectives:
- finding defects;
- gaining confidence about the level of quality and providing information;
- preventing defects.
The thought process of designing tests early in the life cycle (verifying the test basis via test design) can help to prevent defects from being introduced into code. Reviews of documents (e.g. requirements) also help to prevent defects appearing in the code.
Different viewpoints in testing take different objectives into account. For example, in development testing (e.g. component, integration and system testing), the main objective may be to cause as many failures as possible so that defects in the software are identified and can be fixed. In acceptance testing, the main objective may be to confirm that the system works as expected, to gain confidence that it has met the requirements. In some cases the main objective of testing may be to assess the quality of the software (with no intention of fixing defects), to give information to stakeholders of the risk of releasing the system at a given time. Maintenance testing often includes testing that no new defects have been introduced during development of the changes. During operational testing, the main objective may be to assess system characteristics such as reliability or availability.
Debugging and testing are different. Testing can show failures that are caused by defects. Debugging is the development activity that identifies the cause of a defect, repairs the code and checks that the defect has been fixed correctly. Subsequent confirmation testing by a tester ensures that the fix does indeed resolve the failure. The responsibility for each activity is very different, i.e. testers test and developers debug.