How to Choose a Software Testing Method

Waterfall Model (Linear Sequential Life Cycle Model)

One of the oldest models available, Waterfall allows you to follow sequential steps only moving on to the next step when the preceding one is complete. It is cost effective and simple and great for small projects with clearly defined requirements. Once the development stage is complete testing starts by looking at the performance of components individually and as part of the whole. It does have some weaknesses including an inability to return to previous steps in order to correct critical bugs found at a later stage.

V-Model (Verification and Validation Model)

This model also follows sequential steps but differs from Waterfall by allowing testing in parallel with each development phase. As soon as the requirements are ready the first test can begin, be reviewed and verified which helps prevents defects emerging at later stages. The V-model is divided into two parts each of which are organized into phases. The main disadvantage of this model is that there is no clear way to eliminate software defects found during the (final) testing phase.

Incremental Model

This divides tests down into cycles which are further divided into smaller modules. Each part adds some functionality and includes three cycles and allows for several product versions to be simultaneously tested until the project is complete. It can find maximum errors in the fastest time and increases the need for stringent requirement and load testing. The one big advantage is flexibility and the cost reduction in making changes, however, the total cost is higher than Waterfall.

Spiral Model

The Spiral Model has 4 main phases and used an incremental approach. Once the first cycle completes, the second one can begin. Spiral produces immediate feedback to assist in QA however it is a costly product so is more suited for larger products. Although one of the older methodologies Spiral is still a useful tool for testing and for software development.

Agile Model

Agile software is aimed at minimizing risk by providing information about the effectiveness of multiple short iterations. It enables a quick response to issues to make change rather than enabling long term planning. Dynamic requirement formation and implementation is a key role of this type of software.

XP (Extreme Programming)

XP involves two colleague where one works with code and the other reviews it. It is a form of flexible software development where testing starts before any code is written, with the aim of identifying errors. This method only allows code to be passed if it passes every test. The main advantages is the high quality of the code it generates as a result of constant testing, however documentation can be poor.

Scrum

With Scrum, another agile methodology, members of the QA team are involved at all stages from release planning right through to automation testing, meeting daily with the rest of the team to discuss and tweak progress. The main drawback is that it can produce a number of challenges to the testers including regression risk which increases as code changes.

There appears to be no one-size-fits-all solution as each project requires different things. Some methodologies are great for early testing, while others need a more developed system. Seeking specialist advice can help you select the one that is right for your needs.