Introduction
Agile is one of the most famous project management frameworks in software development that follows the principles of agile software development. Agile testing is a dynamic and collaborative approach that helps teams deliver high-quality software while responding to changing requirements and customer feedback. It promotes a culture of continuous improvement and customer-centric development.
Agile testing
Agile testing involves all members of a cross-functional agile team, with special expertise contributed by testers, to ensure delivering the business value desired by the customer at frequent intervals, working at a sustainable pace. Agile testing allows testing to happen in a more timely and efficient manner by breaking testing down into "bite-size" blocks. It supports DevOps and continuous testing, which is important for improving product quality.
In agile testing, there are various roles and responsibilities for different team members. Agile testing can be challenging because agile teams move quickly and are constantly making changes, so testers need to be adaptable and able to change their approach on the fly. Agile testing covers all types of testing, and the Agile Testing Quadrants provide a helpful taxonomy to help teams identify and plan the testing needed. This methodology also allows testers to get immediate feedback from customers.

Principles of Agile Testing
Agile principles refer to a set of guiding values and practices that underpin the Agile methodology, which is an approach to software development and project management.
The Agile Manifesto, created by a group of software developers in 2001, outlines these principles and serves as a foundation for Agile methodologies like Scrum, Kanban, and Extreme Programming (XP).
Here are the 12 principles of Agile as stated in the Agile Manifesto:
Customer Satisfaction through Early and Continuous Delivery of Valuable Software: The primary focus is on delivering valuable working software to customers as early as possible and continually throughout the project.
Welcome to Changing Requirements, Even Late in Development: Agile processes should be adaptable to changing customer needs and requirements, even if changes occur late in the development process.
Deliver working software frequently: Frequent and regular delivery of working software builds trust and allows for continuous feedback from customers and stakeholders.
Collaboration between Business People and Developers: Close and continuous collaboration between business stakeholders and development teams is essential to aligning the software with customer needs and business goals.
Build Projects Around Motivated Individuals: Give motivated individuals the autonomy and support they need to get the job done and trust them to deliver.
Use face-to-face communication as much as possible: Face-to-face communication is more effective than written documentation or emails for conveying information and resolving issues.
Working Software is the Primary Measure of Progress: The ultimate measure of progress is the delivery of working software, not just the completion of tasks or documentation.
Maintain sustainable development pace: Agile teams should work at a sustainable pace, avoiding overwork and burnout, to ensure long-term productivity.
Continuous Attention to Technical Excellence and Good Design: High-quality software requires a focus on good design and technical excellence. This reduces technical debt and makes the software easier to maintain and extend.
Simplicity, the Art of Maximising the Amount of Work Not Done: Strive for simplicity by doing only what is necessary and avoiding unnecessary features and complexity.
Self-organizing teams make the best decisions: Give teams the autonomy to make decisions about how they work and what they deliver, as they are best positioned to understand the work.
Regular Reflection and Adjustment: At regular intervals, the team reflects on their work processes and adjusts them to improve efficiency and effectiveness.
The roles and responsibilities of testers in agile testing can vary depending on the specific project and team, but here are some common responsibilities:
The Agile Tester: The Agile Tester plays a central role in ensuring the quality of the software. They are responsible for testing the software, identifying defects, and working with the development team to fix them. They also help to ensure that the software meets the customer's needs and is delivered on time.
Creating and Providing Feedback: Testers in an agile team are responsible for creating and providing feedback on test status, test progress, and product quality. They work closely with the development team to ensure that defects are fixed and that the software meets the customer's needs.
Analyzing Requirements: Testers in an agile team are responsible for analyzing the requirements from user stories and understanding the functionality of the feature. They work closely with the development staff in all phases of development.
Writing Automated Tests: Agile testers may support developers in writing unit tests and creating excellent automated tests. They may also write automated tests before coding the functions, using a testing-first methodology.
Working with Product Managers and Customers: Testers on agile teams work closely with product managers on defining features and with customers on feedback. They ensure that the software meets the customer's needs and that it is delivered on time.
Retesting Functionality: Testers in an agile team are responsible for retesting functionality and applications following the release of fixes. Bugs should be reported as soon as they appear, and the tester should work with the development team to fix them.
Agile testing differs from traditional testing methods in several ways. Here are some of the main differences:
Continuous Involvement:
In traditional testing, the test team works mostly in a silo, and there is little or no interaction needed with developers or other teams on a daily basis. In contrast, in agile testing, the test team is integrated with the Scrum team instead of being a separate unit. They need to be continuously involved in all aspects of the project, starting with the requirements and design of each feature.
Quick feedback from testing:
The most important difference for agile testers is the quick feedback being given from the testing perspective at every point. In agile testing, testing is done incrementally and interactively, building up each feature until it provides enough value to release to production. This allows for quick feedback and the ability to make changes on the fly.
Iterative Approach:
Traditional testing follows a top-down approach and a more predictive model, wherein testing is executed step-by-step. In contrast, the process of agile testing follows an iterative approach and an adaptive model. Agile testing follows a philosophy of testing first, wherein defects are fixed during each sprint and then released.

Test Automation:
Both agile testing and traditional testing make use of the same techniques, including automating smoke, regression, and functional tests. However, in agile testing, test automation is a key component, as it allows for quick feedback and the ability to make changes on the fly.
Exploratory Testing:
Exploratory testing is a cyclical method, progressing from test design > test execution > analysis > learning before repeating the cycle. Exploratory testing is used in both agile and traditional testing, but in agile testing, it is a key component as it allows for quick feedback and the ability to make changes on the fly.
Conclusion:
Agile principles provide a foundational framework for flexible and customer-centric approaches to software development and project management. These principles prioritize collaboration, adaptability, continuous improvement, and delivering value to customers. They are encapsulated in the Agile Manifesto, which has guided the development of Agile methodologies such as Scrum and Kanban, enabling organizations to respond effectively to changing requirements and deliver high-quality results.