There are several different models in the software development life cycle. Some of them are mentioned here. The basic phase and activity are the same for all the models. They are mentioned below:
- Waterfall model.
- V-Shaped model.
- Agile model.
1. Waterfall model
The waterfall model is also known as a linear sequential model. It is the very first model in the software testing life cycle. Once phase output is input for another phase. The next phase starts only when the previous phase is completed. The step by step process is mentioned below:
- Requirements Analysis.
- System design.
- Implementation/Coding.
- Testing.
- Deployment.
- Maintenance.
Requirement Analysis
In this phase, requirement gathering is done for the application. SRS(Software Requirement Specification) documentation is prepared in this phase. This is the input for the next phase.
System Design
System design is prepared in this phase by studying the (Software Requirement Specification)SRS document. This design is useful to know the requirements of hardware as well as the system. And also defines the architecture for the overall system.
Implementation/Coding
In this implementation/coding phase coding is done by the developers by thoroughly studying the (Software Requirement Specification) SRS. This developed software is input for the next phase.
Testing
The software code is tested by the tester thoroughly to find the defects. If any defects are present then defects are logged into the defect tracking tool. Until the time the software is in go-live state bug logging, retest, regression goes on.
Deployment
After the sign off is given by the customer in the Deployment phase, the developed code is moved into production.
Maintenance
If any issue arises in the production environment developers will resolve it.
The advantages of the Waterfall model:
- A simple model and easily understandable.
- Deliverables of each phase are well-defined.
The disadvantages of the Waterfall model
- It is a time-consuming process & cannot be used for short duration projects.
- Not used for the type of application in which requirements are keeps on changing.
2. V-shaped model
It is known as the verification and validation model. In this model development and testing goes parallel. There are two main phases in the v-model.
- Verification phase.
- Validation phase.
Verification phase
The following are the steps involved in this phase.
- Requirement Analysis.
- System Design.
- High-Level Design.
- Low-Level Design
- Coding
Validation model
The following are the steps involved in this phase.
- Unit Testing.
- Integration Testing.
- System Testing.
- Acceptance Testing.
The advantages of the V- shape model
- Good for smaller projects.
- It is a systematic and disciplined model which results in a high-quality product.
The disadvantage of the V-shape model
- Requirement change costs too high.
3. Agile model
It is a combination of an iterative and incremental model. This model focuses more on development rather than a requirement. The application is divided into small incremental builds. In this iterations are termed as sprints. At the end of each sprint, the product owner verifies the product and after his approval, it is delivered to the customer.
The advantages of Agile model
- New features can easily be added.
- Customer satisfaction as the feedback and suggestions are taken at every stage.
The disadvantages of the Agile model
- Lack of documentation.
- High skilled resources are required.
