Extreme programming (XP) is a specialist programming strategy that enables coders to quickly incorporate changes in the final build. This specialist technique prioritizes efficient code delivery through shorter development cycles and periodic releases. It emphasizes client feedback and allows programmers to build higher-quality software products through customer observations.
This software delivery model was developed in the ’90s by Kent Beck. This framework enables software engineers to deliver software at a sustainable rate. It takes its name from the idea that the best elements of traditional software development (such as pair programming, TDD, and CI) are taken to an extreme level.
In this software development methodology, code creation takes precedence over all other project tasks, such as documentation, role assignment, etc. In this model, feedback and communication between the client and developer are very important. That is the basis of creating user stories, i.e., feature requirements by the user to the dev team.
For Which Projects Should You Use Extreme Programming?
XP development methodology requires a huge client contribution and is very useful for short-term remote projects. You can also use it for research projects that involve new technology and adjustment since this model is very suitable for easily incorporating new enhancements in the project scope.
In this methodology, transparency within the team, as well as with the client, is important. The workspace should facilitate communication (one-to-one if required) and be free from distractions. Many companies also hire XP coaches and trackers to track progress and guide the team in the different aspects of XP.
Since this model requires the developers to quickly pull off changes, the developers have to be flexible in terms of implementation and planning activities. Normally, product teams maintain weekly development cycles for incremental development. This ensures that features and modules are imported every week after unit and integration testing. The releases are done in a quarterly fashion and are made available to all stakeholders.
Phases of the Extreme Programming Model
1. Planning
This is the first phase of XP software development, where the client and development team sit together to discuss project requirements. The management breaks client requirements into user stories and chooses a productivity tool to track them. The development team creates a roadmap for project delivery and provides estimates to track deadlines.
XP projects are tracked through iterations of one to two weeks, after which the enhancements are demoed to the client. The demo allows clients to inspect the final product and provide any relevant feedback to the development team.
2. Design
This is the product ideation phase, where the development team leads connect with the client to brainstorm and design the product’s main features. At this stage, they deliberately keep the project’s complexity and redundancies low to reduce the time required to build the product This also reduces the time to market.
Project designers/engineers are also tasked with ensuring that the design logic is simple and easy to follow. This means that the product design should clearly state the intent and structure of the application and should have no duplicate code. The classes and methods should also be kept as few as possible.
3. Development
The next stage is product creation, where developers and system engineers develop the actual code for the project. The code is created in a structured manner and follows standard naming conventions. The project is broken into tasks and engineers use coding principles such as pair programming and collective code ownership for product development.
In pair programming, two programmers work together on the same module. After general ideation, the first engineer programmer writes the code, and the second one reviews it. The second engineer is also tasked with other tasks such as bug fixing, code refactoring, enhancement suggestions, etc. The final module is constantly refactored for accuracy and efficiency.
In XP, the whole team maintains ownership and accountability of the product. In addition, all of them have access to design docs and know where to add/remove code information. This way, the whole team can collaborate on the different aspects of the project if required. This cross-functional method of code maintenance is called collective code ownership.
4. Testing
In this phase, the final product gets tested for code quality and bugs. Testers use extensive unit and integration testing techniques on each module to ensure that client requirements are satisfied.
This consecutive approach of testing modules before adding them to the dev branch is called test-driven development (TDD). This ensures that modules work properly before they are integrated into the build. You can also use test automation techniques for this.
The approach of adding small incremental changes to a branch through CI pipelines is called trunk-based development. This helps developers avoid merge conflicts and reduce risks associated with branch integration.
5. Feedback
Based on user stories, the development team creates Spikes, i.e., project modules similar to a prototype. These Spikes are then demoed to the client. This is called acceptance testing. In this process, the client looks at the product and verifies that it is according to their requirement.
Immediate feedback from the client is collected and used for further product development. This sometimes requires face-to-face communication with the client. This feedback is then incorporated into the project incrementally.
What are the advantages of using XP development methodology?
There are several advantages to using XP for your project. Let’s have a look at them.
1. Reduces development time
XP allows developers to develop products faster than other methodologies through rapid client feedback and frequent product releases.
It emphasizes the role of the client by allowing them to add changes to the product during the development cycle. Once they propose changes, developers implement those changes and improvements quickly in the form of short development cycles called iterations.
Each iteration lasts 1-2 weeks, in which developers adjust the product according to the client’s recommendation. If required, developers can also implement new features.
All iterations include the standard XP development steps (planning, coding, testing, etc.) and allow developers to fix issues continuously in a timely manner. This helps them continuously improve the project with small, gradual changes.
2. Decreased individual workload
The goal of this process is to write well-documented code with good structure to deliver functionality. XP uses pair programming to achieve this. In this process, as mentioned above, two programmers sit together to solve a particular problem and work on issues.
This allows developers to have more confidence in their work and reduces the risk of errors. It also increases the project’s efficiency and improves the knowledge transfer (KT) process.
This also helps engineers improve their interpersonal skills and allows them to write well-factored code.
3. Increased project flexibility
XP allows developers to use short, incremental development cycles to solve customer issues on time. This increases the flexibility of your project and allows clients to adapt to changes in the product.
This also reduces the risk associated with developing new software/features and enables developers to manage unforeseen challenges one at a time. Instead of planning and creating the whole project in one go, it empowers developers to design features one by one in different iterations.
This “just in time” approach is incredibly helpful to development teams looking to incorporate market changes and changing customer requirements into the project. Thus, in the end, the developers can deliver a product that fully satisfies their customers.
4. Improved communication between the client and the development team
XP promotes frequent developer-client communication and enables developers to deliver high-quality software through iterative building. It also emphasizes communication between the developer team and other stakeholders to ensure that everyone associated with the project has a channel to ask questions and define their specific project requirements. This allows developers to incorporate ideas and changes from all stakeholders, not just the client’s management team.
That’s why organizational leaders invite all necessary stakeholders to plan and review sessions in XP. Such frequent customer involvement helps iron out product issues and build a better project.
XP also requires managers to use project management tools such as JIRA and Trello to enhance project visibility and make sure that all stakeholders know exactly what’s happening in the project. They can also use ad hoc tools such as ServiceNow to monitor progress and track the amount of work done. The use of these monitoring tools also helps to assure the relevant stakeholders that the project will be completed on time.
5. Customer Success
The very purpose of choosing the XP methodology is to increase customer satisfaction and improve internal and external communication. This methodology also promotes customer involvement in the build and enables them to be a part of the development process.
XP is a surefire way of improving customer satisfaction since they are actively involved in the different stages of project development, such as planning, development, and reviews. All customer changes are quickly integrated into the project, improving project deliverability and ensuring that the final product satisfies all client concerns and demands.
Furthermore, In XP there is no pressure to identify and list out all the project requirements during the initial meetings. Even if the project requirements get changed midway through the project, XP provides clients with a way to incorporate those things into the final build.
6. Improved overall code quality
Techniques such as pair programming and test-driven development allow managers to ensure that the code added to the module is of the highest quality. Furthermore, XP also uses continuous integration and automated testing techniques tools to save time and ensure an error-free build generation.
All production code is automatically tested through integration and module tests before getting added to the repository to ensure that it is free from bugs. It also makes sure that code is refactored properly according to the project guidelines.
This is important since you might need to change/maintain the code in the future. You can also easily scale the refactored code if required.
Some common pitfalls to avoid when using XP for your development
Even though XP is a great development methodology with benefits such as improved code quality and reduced individual workload, it has a few issues too. Let’s have a look at common pitfalls software development teams can fall into while following this methodology.
1. Unclear client instructions
This development methodology puts customers at the center of the whole developmental process. This means that developers need customer involvement and feedback to complete their work. However, in some situations, the client’s requirements are not adequate.
If a client fails to give proper requirements to the developers or is unclear about their needs, it severely undermines the whole concept of feedback-based development and impacts the developer’s progress. The developer won’t be able to understand the way forward and hence won’t be able to create a product that satisfies client requirements.
2. Pair programming issues
Even though pair programming is a great way to develop new software, sometimes it can be harmful to the overall project’s progress. Developers who are not used to this process will have problems adapting to it.
Furthermore, finding two developers who have great compatibility with each other can be difficult. If the team is short-staffed, using pair programming can actually increase the time required to finish the project since two developers will be working on a single ticket.
3. Adapting to new developmental methodology
Understanding XP and working with an iteration-based development model can be difficult for developers who have not previously worked with it. This can be especially challenging for developers who are used to traditional working models such as waterfall and iterative models.
Moreover, since requirements can change at times during the project, this methodology can frustrate developers and cause them to resist this methodology. In addition, this developmental style can bring uncertainty to the project since the team has very little control over the process.
4. Difficult with timeline estimation
All developmental projects require vendors to adhere to a strict timeline in which they are required to deliver a project. This is also mentioned in their SLA. Most software development teams make these estimations at the start of the project when the SLA is made.
However, adherence to these deadlines can be difficult in XP, where the requirements are constantly changing. Moreover, sometimes the clients themselves delay the feedback process, which can, in turn, delay the whole process. Hence it becomes difficult for managers to exactly predict the project delivery dates and to control the process.
5. Project collaboration
XP relies on frequent high bandwidth communication between the team. Hence it should only be implemented in projects with a small team size (less than 20 people). Ideally, they should also be collocated.
Implementing this methodology in larger teams can cause communication issues, which can increase product development time. In addition, since it requires so much collaboration, this technique is unsuitable for large, complex projects that might need many people to cooperate with each other.
Lastly, this strategy is impossible to implement without the support of good managers and team leaders. The leader/XP coach helps the team understand the development process and makes sure they accept and follow XP principles.
They are tasked with setting up a balanced work culture and supporting the communication between the development team and the client. If required, they should also mentor the team and help them stay on the project goal/process. Without adequate support from the management and company leaders, the team will definitely face difficulty adapting to the process.
6. Setting up automated testing
The core of XP implementation is CI and test automation since they ensure that all modules are tested and verified before getting added to the master build. If your company doesn’t have automated testing in place, or if your testing tools don’t work correctly, it can significantly impact code quality and developer efficiency.
Test automation can take a lot of time and effort to set up. First, the QA team needed to choose the required tool and create the automated test cases. This requires a huge upfront investment from the organization, which is not feasible sometimes.
The QA team also has to maintain these test modules and ensure that they run every time before the code is added to production. They must also test for real user inputs before sending the code for build generation. This may require setting up expensive infrastructure, which can be difficult to maintain. You might also need to upgrade it as per newer market standards (for example if there is a new device launched in the market with a different screen size).
Lastly, even if you implement test automation in your CI pipeline, it won’t be able to test for all use cases. Tests such as UI/UX and cross-browser compatibility tests will still need a human element. This means that apart from test automation tools, you also need experienced human testers on your team.
Conclusion
XP is an amazing Agile software development approach that encourages change rather than avoiding it. It is very helpful for developing high-risk projects with new technologies. In this methodology, there are no long-lasting development phases — each iterative phase lasts between one and two weeks. QA teams are encouraged to use test automation techniques and frameworks to analyze and evaluate modules before marking them as passed.
XP differs from other Agile methodologies as it accentuates good software development practices over everything else. It also encourages policy refinements in favor of implementation, which is in contrast to other Agile methodologies such as Kanban and Scrum. There are no rigid roles but a general knowledge-sharing approach to product development.
