There has been a lot of buzz around Agile in the software engineering and application development world. Agile is not a concept, but a mindset. As the name suggests, it concentrates on being flexible and dynamic. This methodology also removes the isolation between the phases of software development, and encourages the development team to collaborate with quality analyst(s). It also emphasizes the involvement of customers to develop, build and deliver a high-quality product. Here we'll take a look at Agile, how it works and some best practices for this popular software development method.
A Brief on the Software Development Life Cycle
The software development life cycle (SDLC) is the process of creating software solutions or modifying the existing structures intended to cater to a particular problem. It encompasses various steps, which are followed in a logical order. In traditional SDLC models, these are the steps that are followed one after the other, and are usually carried out in isolation:
- Requirements gathering from the clients
- System and feasibility analysis
- Design and modeling
- Coding or implementation
- Deployment and delivery
- Maintenance and change requests
In a typical software development cycle, the actual users, or clients, are involved in the process of requirements gathering and then during beta testing. However, the problem with this traditional model is that the maintenance part of the cycle becomes a difficult and rather expensive affair. Many a times, there is no scope for enhancements or changes within the system. In a worst-case situation, the software that has been engineered or developed is not in line with the actual customer specifications and expectations, which means the development team may need to start the whole process all over again.
Why Agile Development's Different
The most common traditional models of SDLC - the waterfall model, rapid application model, iterative model, spiral model, etc. - have their own set of pros and cons. It took ages before people could actually analyze how realistic these models were. They fit perfectly into ideal scenarios, but they weren't always practical when it came to real-world applications. As a result, software development teams faced a lot of challenges. Some of the limitations of conventional SDLC models include:
- They do not allow requirements to be changed at the later stages because these are frozen in the software requirements specification document. In certain cases, the users' expectations go unstated or misunderstood.
- The end users do not see the system until it is complete. This provides very little scope for making suggestions and changes.
- Traditional SDLC can create a huge communication gap between developers and testers, as they are separate phases, and there is no collaboration between the two parties.
- White box testing cannot be done effectively.
The use of Agile resolves many of these problems because rather than a step-by-step process, it acts as more of a philosophy and framework that aims to help teams collaborate, respond to change and build a finished product that includes more input from all parties, including users.
The emergence of Agile methodology is no less than a revolutionary reform in the software development methodology, because it provides enough room for the project teams to be creative and versatile while still taking collective ownership of each phase of the product. By following the Agile path, individual participants in the software development team are able to condition their minds to embrace uncertainty, cope with changes, and build a better product as a process, rather than in discrete, unattached steps.
Although there is no comprehensive list of Agile principles, there are certain practices that Agile propagates. These include:
- Test Driven Development (TDD)
Ideally, developers should first write test cases for the piece of functionality they are going to code for. This will ensure good-quality code, which is less likely to break in exceptional conditions. This process also helps to ensure that user specifications have been addressed.
- Pair Programming
In Agile development, programmers generally work on the same problem in pairs, where one person is writing the code (driver) and the other one is reviewing the code and providing ideas and suggestions (navigator). This enhances productivity and reduces the time required to review code.
- Code Refactoring
Code refactoring involves breaking down the code into smaller and simpler modules that can (and should) exist independently in the ideal scenario. This improves the readability, testability and maintainability of the code to a great extent.
- Active Participation from Actual Stakeholders
Following regular intervals of a definite time period (referred to as "sprints"), clients should receive a significant working prototype of the software. This allows developers to get feedback on what they're building as they go.
- Treat Requirements as a Prioritized Stack
In Agile, it is essential to categorize requirements on the basis of their importance. This may include both implicit as well as explicit customer expectations on the software product being developed. The software development team should collectively estimate the time and resources they are going to invest into implementing the feature, and map that based on user requirements and the relative order in which they'll be tackling each part of the project.
- Regression Testing
Regression testing involves testing the functionality of an entire application after adding a new feature or modifying the existing functionality in the code. This helps to ensure that the changes have not broken the existing code.
Why Go Agile?
Agile prescribes certain practices, but it does not enforce them upon a software development team. After all, if there is no scope for adjustments and deviations, the purpose of Agile is largely defeated. Incorporating even a few aspects of Agile development into a project can help software development teams cope with unanticipated challenges and, ultimately, build a better product in a more efficient way.