10.4 Testing Process

The basic goal of the software development process is to produce software that has no errors or very few errors. In an effort to detect errors soon after they are introduced, each phase ends with a verification activity such as a review. However, most of these verification activities in the early phases of software development are based on human evaluation and cannot detect all the errors. This unreliability of the quality assurance activities in the early part of the development cycle places a very high responsibility on testing. In other words, as testing is the last activity before the final software is delivered, it has the enormous responsibility of detecting any type of error that may be in the software.

Furthermore, we know that software typically undergoes changes even after it has been delivered. And to validate that a change has not affected some old functionality of the system, regression testing is done. In regression testing, old test cases are executed with the expectation that the same old results will be produced. Need for regression testing places additional requirements on the testing phase; it must provide the old test cases and their outputs.

In addition, as we have seen in the discussions in this chapter, testing has its own limitations. These limitations require that additional care be taken while performing testing. As testing is the costliest activity in software development, it is important that it be done efficiently.

All these factors mean that testing...