Extreme Programming Tutorial: Comprehensive Guide With Best Practices

Extreme programming, or XP, is a typical agile development framework based on discovering the simplest thing that works without putting too much effort into long-term product view. It provides principles and values to guide the team's behavior.

Although XP can be leveraged as a stand-alone agile approach for highly experienced teams, it truly shines when combined with Scrum or other Agile methodologies.

Starting with methodologies like Scrum or Kanban to provide the required level of structure for controlling the flow of work, XP and its emphasis on best practices greatly help teams attain high maturity levels.

What Is Extreme Programming (XP)?

Extreme programming (XP) is a software development methodology built on values, principles, and best practices. Its goal is to allow small to mid-sized teams to produce high-quality software and manage changing customer requirements.

What sets it apart from the other agile methodologies is that XP focuses on the technical aspects related to software development. It is all about following the best practices, as the right engineering practices can go a long way in delivering high-quality code at a sustainable pace.

It introduced a newer method of innovation and growth in the software development ecosystem. It was in the year 1997 when Ken Beck, a software engineer and an active contributor to the agile manifesto, created extreme programming. Organizations have relied on XP concepts to accomplish their software development goals.

Core Values of Extreme Programming

The following five core values drive the values of XP.

1. Communication: It is about active communication between different team members to help deliver quality outcomes. The development team ensures that the development status and updates are communicated on time. The team is also part of daily standup meetings where the project progress is tracked and discussed.

2. Simplicity: It is simplistic in the development approach and execution. The development team strives to write simple code that brings more value to the product, saving time and effort. The project is also broken down into simple phases to make it easier for the teams to manage overall delivery and quality aspects.

3. Feedback: Timely and constructive feedback from customers helps to deliver quality software. The team members get feedback once the software is delivered frequently, which allows them to bring much-needed improvements to the new requirements.

4. Value: Extreme programming is about working towards a common goal where each person's contributions and opinions are always given the required importance.

5. Courage: You need to evaluate your results without making any excuses and are always ready to respond to changes. The respective team members are accountable for their tasks and must find ways to improve in the long run.

Principles of Extreme Programming

In this section, let's explore the principles of XP.

• Constant and early feedback: Feedback is a traditional approach followed in the waterfall software development methodology. XP embraces change, and the teams strive to receive early and constant feedback. If you need to change or redefine the existing processes, you can do it as soon as possible.

Feedback can come in many different ways. One such instance is pair programming, where the vital comments from your peers act as feedback for making improvements. It is important to handle feedback comments constructively.

• Assumed simplicity: Developers need to focus on tasks with the highest priority and maximum business impact.
• Incremental changes: It is about making small and iterative changes to the product rather than building the entire product in one go. When you perform incremental changes, you get constructive feedback from the customers that help you improve the existing product.
• Embracing change: It is all about considering the customer's viewpoints and opinions and then adapting to the change. If a client thinks that a product functionality needs to be changed, the development team should support this decision and plan how to incorporate the new requirements.
• Quality work: The team collaborates closely to deliver quality output within stipulated timelines.

Important Roles in Extreme Programming

As important as XP's process is for timely delivery, four important roles play a crucial role in its success. These are as follows.

1. Customers: Customers are expected to be heavily involved and engaged in the development process by creating user stories, providing continuous and timely feedback, and making all the required business decisions that impact the project.

2. Developers: The developers or programmers are the team members that create the product. They are responsible for implementing the user stories and conducting user tests.

3. Trackers: The trackers or managers act as a link between customers and developers. This role can be performed by any of the developers that are well-equipped. These people organize meetings, initiate essential discussions, and keep track of agile metrics such as sprint velocity, burn down chart, etc.

4. Mentors: One can include mentors in the team to help execute XP best practices. It is usually an external consultant who is not part of the development process but has used XP before and is well aware of the challenges or issues.

Advantages of Extreme Programming

Here are some of the advantages of XP since this framework helps to reduce development time and costs:

• XP encourages continuous testing and refactoring practices that create well-performing and stable systems with minimal debugging.
• Product development is performed using small iterations where client feedback is considered. The changes are done per the customer feedback, which helps to save a significant amount of development effort and reduces costs.
• You can create clear and concise code which is easily interpreted and can be changed in the future if required.
• The documentation is reduced as long requirement documents are replaced by user stories.
• There is constant communication throughout the entire development process allowing all the team members to keep track of the project's progress and delivery.
• The concept of pair programming ensures that higher-quality products are built with fewer bugs.
• Customer engagement ensures that the product requirements are developed per the desired expectations.

Disadvantages of Extreme Programming

Here are some of the disadvantages of XP.

• In many scenarios, customers are not sure of the exact requirement, which makes it challenging to define scope, cost, and time accurately.
• XP relies too heavily on programming principles, where the design is often overlooked. This can be challenging when your product contains a lot of design changes that make a difference in the end-user experience.
• There are regular meetings with customers, which often take a great deal of time that could be spent on writing the code.
• The rapid transition from the traditional approach to XP demands a lot of cultural and structural changes.
• Sometimes, customers do not have the time or expertise to participate in product development. If we have strict timelines, it becomes a problem as valuable feedback cannot be provided on time, impacting the overall quality.

Extreme Programming (XP) vs. Waterfall Methodology

Let us try and compare extreme programming and traditional methodologies like a waterfall and see the major differences between the two.

When To Use Extreme Programming?

These are the following scenarios where you can use XP and its related principles:

• Small teams: XP practices and values work effectively for smaller teams (less than 12 people). It becomes easier to manage small teams as communication is seamless, and it takes less time to conduct meetings and code review sessions.
• Automated tests: The ability of the development teams to create and perform automation testing using standard tools and frameworks.
• Active customer participation: XP is all about customers' active participation with different project stakeholders. The quality output is ensured if the customer is always available to provide inputs until the project is executed.
• Ready to accept new culture and mindset: XP is entirely different from the traditional software development approach. It becomes important for the organization and associated teams to embrace changes. It will also require changing the overall mindset and ways of working.
• Highly adaptive development approach: XP works perfectly for systems with frequent changes. The framework is designed to help development teams adapt to changing requirements quickly and perfectly.

The Lifecycle of Extreme Programming

XP can be explained using weekly and quarterly cycles. The customers define the user stories. The estimation of the user stories is done by respective teams taking into consideration the customer impact and value proposition.

The team can introduce a spike if some of the stories cannot be estimated due to unclear expectations. This means that the teams can take additional time to research and then start with the stories in the same or next releases.

The release plan covers the stories delivered in a particular release or quarter. The weekly cycles begin when the team and customer interact and decide on the user stories to be picked up every week. These stories are broken down into tasks that need to be completed within that week. A review happens on weekends to review the overall progress and decide whether the required business value was delivered.

Phases of Extreme Programming

Extreme programming (XP) involves five phases or stages of the software development process.

1. Planning: This is the first phase, where the customer meets the development team and presents the requirements. The product owner and the development team convert these requirements into user stories. The team estimates the user stories and creates a release plan into iterations where the required functionality is delivered individually. If one or more stories are not estimated, further research is needed.

2. Design: It is a part of the planning process but can be set apart to highlight its importance. It is related to one of the XP values known as simplicity. A good design brings much-needed consistency to the system and helps to avoid unnecessary complexities.

3. Coding: This is the third phase, during which the actual coding requirements are executed using standard XP practices such as coding standards, pair programming, continuous integration, and collective responsibility of code.

4. Testing: This is one of the core phases of XP. The team performs unit testing to check the developed feature and acceptance tests to ensure that the overall system is created per the defined requirements.

5. Feedback: This phase is all about constant communication and feedback. The customers and project managers determine whether the expected value is delivered.

Extreme Programming for Achieving Business Goals

XP is all about following the best practices and values of software development. It is also about utilizing the full potential of the development teams so that you can achieve desired business goals and objectives.

Here are the key pointers you need to consider.

• Face-to-face team interactions are more productive and valuable than working in silos.
• Evaluating and managing the workload of different team members effectively so that top-notch quality is delivered every time.
• Setting up a short team and long-term goals that align with the business needs.
• Setting up clear expectations regarding product delivery.
• Seamless communication between all the different project teams.

However, there are always challenges for organizations and enterprises to achieve agile or XP objectives to accelerate their product growth and strategy. Also, it is crucial to quickly include the developer feedback in every release or iteration so that review comments are included within the stipulated timelines.

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• Expedite testing, reduce job times, and get faster feedback on code commits with Test At Scale.
• 120+ third-party integrations with tools for CI/CD, codeless automation, and more.

Case Studies for Extreme Programming

The following are some case studies illustrating how XP practices changed project delivery dynamics and quality.

XP for Krizp System

Krizp System was a startup providing web development services in India. They used to create web portals for other small companies or educational institutions. They had no defined framework for software development processes as it was a startup with few employees and limited resources. The requirement-gathering process was not structured, and it became a lot more challenging to handle the requirements when the customer proposed changes to the existing requirements that were delivered.

The developers were not communicating frequently as they worked independently on different modules or components. There was no project manager to track the progress and health of the project or even make sure that there were regular interactions with customers so that the product requirements were developed as per their expectations.

The team at Krizp system was introduced to the concepts related to different Agile frameworks, and this is when XP methodology was introduced for one month. The company's CEO took up two roles – customer representative and tracker. This meant that the user stories prioritization, regular customer interaction, and handling development teams seamlessly.

The pair programming technique was adopted when developers were working together. The design improvements were made based on customer feedback and inputs. The concept of XP positively impacted the company's overall software development cycle, with better team productivity and effective product deliveries.

XP for IBM and Sabre Airlines

The researchers at IBM wanted to study the impact of XP on different crucial aspects such as productivity, customer satisfaction, etc. There were two different approaches – waterfall and XP for developing their applications. The final results indicated that XP is a far better approach than waterfall.

In another case study at Sabre, Airline Solutions followed two approaches to release the same product. Delivering the release took 3.5 months using XP compared to the waterfall, which took 18 months. This shows how XP creates a larger business and customer impact from an output perspective.

Let us try and understand the concept of cross-browser testing, which has gained much popularity in the past few years.

Best Practices of Extreme Programming

The core of XP lies in implementing the software development practices detailed below.

• Extensive planning: Agile methodology is all about having a comprehensive planning process known as the planning game. There are two levels of planning – Level one is release planning and Level two is iteration planning.

  The release planning phase is about finalizing the requirements, where all the required project stakeholders decide on the features and enhancements delivered in every iteration. The features and enhancements to be delivered are prioritized based on the customer impact and business value. The Iteration planning follows a similar practice where you decide on the iteration as part of this phase.

• Small releases for better product delivery: It is about delivering quality outcomes in small releases that ensure that you deliver a Minimum Viable Product (MVP), helping you to meet customer expectations. With small releases, you can easily manage your project requirements as they can be broken down into sub-tasks. The development team can work on tasks with the highest priority and not waste their time on tasks that have no relevance.
• Metaphor: It is defined as the long-term visualization where every team member who is part of the project should have a high-level understanding of the overall system and coding requirements. This can be accomplished by conducting brainstorming sessions related to the codebase, overall design, and architecture.
• Simple design: You can achieve your desired business goals and objectives using a simplistic design. It is easier to comprehend and can easily pass the required validation tests. You are not required to revisit your code requirements if the design requirements implemented are simple in approach and execution.
• Test-driven development: It is a common approach followed for developing simple, easy-to-manage, and thoroughly tested code. It works on an iterative approach to software development. The code is written to ensure that the test cases that are failing can pass. You can even perform code refactoring for better code performance.
• Refactoring: Code refactoring is a common process in most organizations looking to improve their existing code requirements. The existing source code is refactored to become more effective and easier to manage. You can minimize the technical debt by cleaning up the existing code. Refactoring ensures that the testing teams can perform required tasks without blockers or challenges.
• Pair programming: It is also known as peer programming, a revolutionary programming technique where the programmers work together at one workstation. While one of the developers works on the code, the other reviews the code and can suggest corrections. The idea behind this practice is that two brains and four eyes can deliver better outputs than one brain and two eyes. Teams that follow pair programming have found improvements in the quality and can solve problems more quickly. This ensures that you create less code to accomplish the desired goals.
• Collective code ownership: This practice highlights the fact that the entire team owns the code. Each team member is responsible for reviewing and updating code. The implementation of collective code ownership encourages the team to cooperate more and be more open to bringing new ideas. No key player exists in this setup, so any developer can fix or handle any issue or bug.
• Continuous integration: The teams use different continuous integration (CI) tools, such as Jenkins, Azure DevOps Pipelines, etc. In this practice, the developers ensure that the system is fully integrated. XP teams work on an iterative development approach as they commit the code changes multiple times during the day, known as continuous delivery.

  Also, the developers discuss which parts of the code can be re-used or shared. It allows them to handle the code requirements effectively and understand the functionality they are trying to build. The shared code base eliminates integration issues.

• 40-hour week: XP projects require developers to be effective and fast in their product delivery, ensuring the quality aspect remains intact. To adhere to these requirements, they should be well-rested. To ensure that the professionals do not feel sluggish or overloaded with work, the total number of work hours should not exceed more than 40 per week.
• Onsite customers: This role is similar to a product owner in the scrum. The onsite customer plays an important role and is responsible for performing the following roles and responsibilities:
  • Making sure that the long-term vision is well-defined and crafted.
  • Defining the scope of the user stories and acceptance criteria.
  • Release planning
  • Defining the definition of done (DOD)
• Coding standards and guidelines: Organizations want development teams to follow well-described and standard coding styles called coding standards. These are the standard guidelines followed in XP.

  It ensures that teams working on different modules or components can follow coding standards for maintaining consistency in the code, style, naming conventions, and use of different system parameters. Using fixed standards and guidelines, you can quickly identify and solve issues once the code is developed.

Wrapping Up

By now, you should have an understanding of the XP framework and how it adds real value to the development ecosystem.

XP is about implementing the essential practices and encouraging the teams to continuously improve their ability to perform them in the existing setup. XP focuses primarily on the technical aspects of developing and implementing practices rather than the management and organizational sides.