Agile testing is testing that runs continuously throughout development rather than as a phase after it. Testers work alongside developers from requirements onward, feeding results back within each sprint, so defects surface while they are still cheap to fix. It replaces the waterfall sequence of build-then-test with a cycle of build, test, learn, adjust.

This guide covers what agile testing is, how it differs from traditional testing, the principles behind it, the four main methods, the agile testing quadrants and life cycle, the metrics worth tracking, and where agile testing is the wrong fit.

Agile testing sits inside a wider QA testing processwhat changes under agile is the timing, the feedback loop, and who is involved.

Introduction to agile methodology in testing

Agile has become the dominant approach to software development, a clear indication of the industry's fundamental shift in how software gets built. "86% of software developers worldwide"

This stems from the critical role agile testing plays in ensuring precision and adaptability, making it an essential force in software development. Understanding its significance and impact is necessary to navigate modern programming.

What is agile software development?

To understand agile testing, it helps to understand what the agile development methodology involves. It's an umbrella term covering many practices that differ from traditional development techniques. The four core values are:

• Focus on people, rather than processes and tools
• A working piece of software is more important than detailed documentation
• Ongoing collaboration with customers matters more than a fixed contract
• Be responsive to change, rather than sticking to a plan

As the name implies, an agile methodology is focused on responding to change. There are many frameworks teams might use, such as Scrum or Kanban, but at the centre of it is a collaborative approach.

A traditional development approach might separate team members based on the area they're working on, slowly adding pieces together to create a finished product. With agile, continuous integration is key — the whole team collaborates and new features are added as they work. It creates a completely different software development life cycle, which is why teams need agile testing methods to match.

Agile testing methodology

Agile testing methodology refers to the approach and set of practices employed for testing software within an agile development environment. In agile, testing is not a separate phase but is integrated throughout the software development lifecycle.

The methodology is rooted in the principles outlined in the Agile Manifesto and emphasises collaboration, flexibility, and continuous feedback.

Our interpretation of agile testing is testing that takes place in, and is suitable for, an agile software development environment. Many types of testing appropriate for other methodologies,  regression testing, feature testing and so on, are also relevant to agile testing. What differs is the methodology: how they align with the release cycle, and the approach to planning and understanding success.

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The philosophy of continuous testing

Agile testing operates under the philosophy that continuous testing is an indispensable part of development, equivalent in importance to coding itself. Testing is integrated into the development process to discover bugs early and frequently. This proactive approach enables testers to identify issues at every stage, propelling the product toward release.

Doing agile vs. being agile

Agile adoption among software development teams rose sharply over recent years. The original cited a jump "from 37% to 86%" between 2020 and 2021, sourced from a State of Agile report]

However, merely adopting agile processes doesn't guarantee an organisation is truly agile.

• "Doing agile" involves implementing agile practices, such as using Scrum or Kanban, dividing work into incremental steps, and employing agile estimation techniques. It reflects the application of agile frameworks without a full organisational commitment.
• "Being agile" requires a holistic mindset shift, extending agile principles to all facets of the business. This involves aligning with the Agile Manifesto's core values, fostering adaptability, and nurturing a culture of continuous learning.

Unlike "doing agile", being truly agile demands a deeper commitment and substantial effort, with a realisation that it's a journey that may span years. It requires breaking away from traditional top-down project management mentalities, embracing flexibility, and fostering an organisation-wide agile mindset.

While doing agile might involve process implementation, being agile entails a cultural shift, emphasising mindset over methodologies. The distinction lies in the depth of commitment and the extent to which agile principles permeate an organisation.

Traditional testing vs. agile software testing

To keep things from breaking in the customers' hands, testers attempt to break it first, and then have it fixed.

In the traditional waterfall method of development, the sequence of events is: requirements → system design → implementation → integration and testing → deployment → maintenance.

With this method, the next step does not begin until the previous step has been fully completed, which means the testing team doesn't receive the product until late in the development cycle. This is a real challenge for your software testing team, as any bugs caught at this point are difficult and costly to eradicate.

Testers who enter the process at this point also cannot ask the right questions or perform the right tests, because there is little feedback from other development team members or from customers. They are forced to wait for the product to come down the waterfall, then use a narrow set of skills to decide whether it should be kicked back a step.

With agile, the test plan is in place throughout. Whenever a new update is made to the code, the test team gets their hands on it, feeding results back directly to the developers. These test cycles can also feature automated tests and a small selection of end users.

Principles of agile testing

The 12 principles behind the Agile Manifesto serve as a roadmap for teams adopting the agile mindset. Translated into testing practice, they produce the following twelve principles of agile testing:

1. Test earlier and more frequently. Starting testing as early as possible — sometimes known as shift-left — lets you fix issues earlier in the development cycle.
2. Automate a greater proportion of tests. The underlying principle is that your supply of tests should be fast and elastic. But be careful: research suggests businesses frequently overestimate the percentage of tests they will automate.
3. Provide continuous feedback. Agile testers do not simply test constantly. They are also responsible for distributing the results of those tests and facilitating feedback from customers to developers, to create a more robust product.
4. Deliver value to the customer. This is the paramount principle. The end goal of every action taken by an agile tester is to create the best product possible for the customer.
5. Enable face-to-face communication. The agile tester's role is to reduce confusion and errors by communicating directly with developers, and by enabling customers to communicate directly with developers.
6. Keep it simple. For testing, that means performing only those tests that are necessary, and all tests that are necessary. For the product, it means delivering the simplest possible product that delivers the most possible value.
7. Practice continuous improvement. Agile testers are keen learners; they are never done learning how to do their job better.
8. Respond to change. Agile testers are adaptable and flexible, keeping up with feedback from user stories as well as changes in the product and the marketplace.
9. Self-organise. Instead of waiting at an assigned seat on the assembly line, agile testers act at every point in the process. They actively seek out problems and bring people together to solve them.
10. Focus on end users. Agile testers are collaborative, preferring human interaction to technology. Their focus on people enables them to deliver a product that prioritises usability and utility.
11. Work with business people daily. Business people and developers must work together throughout the project. It helps the development team comprehend customer-requested changes and incorporate them into smaller increments.
12. Review regularly. The team should regularly assess its performance, reflecting on ways to enhance effectiveness and adjusting its behaviour accordingly.

What is the ideal profile of an agile tester?

These principles contribute to the definition of an ideal agile tester profile. Generally, agile testers possess the following characteristics:

• Acute communication skills
• A diverse, technical skillset
• Familiarity with a variety of testing tools and test automation
• An ability to collaborate effortlessly with others
• A willingness to embrace change
• An ability to liaise with everyone from DevOps to business analysts
• Broad experience in exploratory testing
• A results-oriented personality
• A passion for delivering business value

4 types of testing in agile

Several methodologies have been developed for agile testing processes. Here are four of the most widely used. No single methodology is perfect for every product, but these frameworks serve as valuable starting points for creating a customised approach.

1. Acceptance test-driven development (ATDD)

ATDD is a variation of test-driven development. It emphasises the collaborative essence of agile testing by involving customers, developers, and testers in crafting acceptance tests from the customer's perspective. Corresponding functionality is developed only after these tests are created. This workflow simplifies the creation of test cases, giving developers direct insight into customer expectations and product usage. By eliminating ambiguity, it reduces the likelihood of significant errors.

2. Behaviour-driven development (BDD)

BDD builds on test-driven development and acceptance test-driven development, adding the identification of correct business outcomes and running tests based on those outcomes. BDD has five steps:

1. Describe the behaviour
2. Write the step definition
3. Run and fail
4. Write code to make the step pass
5. Run and pass

3. Exploratory testing in agile

Exploratory testing follows a cyclical process: test design, execution, analysis, learning, then back round again. Unlike scripted tests, agile testers generate tests dynamically as they explore the product. Exploratory testing provides the experience closest to how the product will behave in the wild. It's a fast way to find out whether you have working software, and it surfaces bugs that other methodologies would miss.

4. Session-based testing

Session-based testing builds on and refines exploratory testing. The strength of exploratory testing — the creativity of the people doing it — can also be its greatest weakness.

Session-based testing remedies this by adding structure. A charter is created before a test session begins. Uninterrupted testing sessions then take place, each focused mainly on a single charter. The session is reported on, and the manager debriefed afterwards. The additional structure ensures all areas of the product are thoroughly tested, and avoids backlogs building in any particular area.

Agile testing quadrants

With so many testing methodologies available, it can be difficult to assess which type of test should be run, how often, when, and by whom. There are acceptance testing, regression testing, unit testing and more — plus the question of whether manual or automated testing suits the current iteration.

Lisa Crispin and Janet Gregory created the concept of agile testing quadrants, which provide a taxonomy for tests:

• The two left-hand quadrants help teams know which code to write and determine when they are done writing it.
• The two right-hand quadrants help teams learn more about the code they have written, providing feedback to the left-hand quadrants.

The agile testing life cycle

The agile testing life cycle is an iterative process that aligns with the overall agile software development life cycle. It comprises five distinct phases:

1. Impact assessment: Also known as the feedback phase, this involves collecting inputs and responses from users and stakeholders. It helps test engineers set objectives for the upcoming phase.
2. Agile testing planning: Developers, customers, test engineers, and stakeholders work together to plan testing schedules, regular meetings, and deliverables.
3. Release readiness: Test engineers review fully developed features to determine whether they are ready for deployment, or need to return to the previous development phase.
4. Daily scrums: Daily meetings monitor testing progress and establish daily objectives, keeping test engineers informed about testing status.
5. Test agility review: Weekly meetings with stakeholders evaluate and assess progress against established goals.

The cycle iterates through these phases in alignment with development sprints, promoting continuous improvement, rapid feedback, and ongoing collaboration.

Advantages of agile testing

Adopting agile testing yields three straightforward but impactful benefits: a happier team, a higher-quality product, and faster delivery.

1. A higher-quality product

Agile empowers testers to uncover defects early by implementing continuous feedback. Testing begins simultaneously with development, allowing bugs to be eliminated as they emerge. Each product iteration undergoes thorough testing during creation, rather than waiting until completion. Continuous feedback and early, frequent testing means testers gain intricate knowledge of the product — knowledge that, combined with customer input, helps developers craft a better product.

2. Fast delivery

In contrast to waterfall testing, where development and market release are often months or years apart, agile testing shortens the development cycle. This ensures continuous customer feedback, allowing the product to adapt to market needs during development and reach customers swiftly.

3. A happier team

The final principle on the agile testing list is intentional: enjoyment. Agile testing fosters tight collaboration among all team members, cultivating a happier, more enjoyable, and ultimately more productive workplace. Developers, testers, and customers collaborate closely to craft the best product and maximise value.

Crispin and Gregory say it best: "A team that guides itself with Agile values and principles will have higher team morale and better velocity than a poorly functioning team of talented individuals."

Disadvantages of agile testing

Agile methodologies are not without challenges. Recognising potential pitfalls is crucial for a balanced perspective.

Organisational and structural drawbacks

• Weakened team structure: Improper implementation can undermine team cohesion and hinder product development.
• Inherent weaknesses: Even when correctly applied, agile methods have gaps — exploratory testing may lack comprehensive structure, and ATDD might not fully consider business outcomes.
• People-centric challenges: The emphasis on people can backfire if testers are excluded from the closely integrated team.
• Dependency on skilled testers: The departure of a skilled agile tester can be a significant setback.
• Hierarchy confusion: With everyone involved in testing, a muddied hierarchy may cause confusion. Scrum addresses this with scrum masters, but there's a risk of reverting to a traditional approach.

Testing-specific drawbacks

• Time constraints: Short iterations put pressure on testing, leading to reduced testing time or inadequate coverage. Some defects may remain undetected until later stages.
• Incomplete documentation: Agile values working software over comprehensive documentation, which can lead to inadequate records of test cases and plans — a problem for future reference or new joiners.
• Frequent changes: Continuous modification to requirements, design and functionality requires testers to adapt quickly and rework test cases.
• Limited regression testing: The emphasis on delivering new features each iteration can squeeze time for regression testing, increasing the risk of breaking existing functionality.
• Lack of end-to-end testing: Focusing on individual user stories within each sprint may neglect testing all components together for system-level integration.
• Dependencies on development progress: If development is delayed or incomplete, testing is blocked, affecting overall timelines.

Agile testing strategy: overcoming challenges and maximising benefits

Blind adoption without considering appropriateness can lead to a weak, crash-prone product. Agile testing may not be the ideal fit when:

• Project scope is crystal clear: If scope is well-defined and unlikely to change, the dynamic nature of agile may add little.
• A single product owner dominates: In projects governed by one stakeholder with minimal requirements, agile's collaborative iteration may not align with streamlined decision-making.
• Skill sets are limited: Agile testing demands deep, broad skills. Traditional methods might suit a team that lacks them.
• The customer prefers waterfall: Agile faces resistance when the customer insists testing follows development sequentially.

Once you have determined that agile testing will benefit your team, product and customers:

1. Select an agile methodology that aligns with your project's needs — Scrum, Kanban, or Extreme Programming.
2. Create a robust testing process using the four-quadrant model to ensure comprehensive coverage.

To foster collaboration and prevent tester exclusion:

• Testers should work as closely as possible with developers, with regular interactions keeping everyone aligned.
• An iterative approach to both testing and collaboration builds connections early, paving the way for smoother work later.
• Testers should provide valuable feedback to developers and customers, making themselves indispensable.

Metrics in agile testing

Three primary types of agile metric have gained prominence across agile frameworks:

• Kanban metrics: Centred on invested time (cycle times) and delivered outcomes (throughput), emphasising the ratio between the two.
• Scrum metrics: Focused on planning, understanding workflow, and illustrating the volume of work accomplished within a timeframe.
• Lean metrics: Ongoing measurement of production efficiency and product quality, incorporating technical assessment through feature testing and error checks.

When testing in an agile environment, focus on metrics that provide meaningful insight into quality, progress, and effectiveness:

1. Test coverage: Measures the extent to which test cases cover the requirements and functionality of the system, identifying gaps and ensuring critical areas are tested.
2. Defect density: The number of defects identified per unit of code or functionality, indicating how many defects are found relative to the amount of code tested.
3. Test execution progress: Tracks progress within a sprint, giving visibility into the percentage of test cases executed and identifying bottlenecks.
4. Test execution efficiency: The ratio of passed tests to total tests executed.
5. Cycle time: How long a user story or task takes to move through the entire testing process, from creation to completion.
6. Defect turnaround time: The time taken to identify, report, fix, and retest a defect — a measure of defect management effectiveness.
7. Customer satisfaction: Not directly a testing metric, but feedback from customers and stakeholders provides valuable insight into testing effectiveness.
8. Agile test velocity: The rate at which testing tasks or user stories are completed within an iteration, indicating testing capacity.
9. Escaped defects: Defects identified by customers after release. Tracking these identifies where testing and QA processes need improvement.

Metrics should be used judiciously and alongside qualitative assessment. They shouldn't overshadow the primary focus on project requirements and audience preferences.

Agile testing best practices

Conclusion

Agile's flexibility and responsiveness to change make it a strong fit for modern software development. Despite potential drawbacks, when employed by a team committed to its principles, the benefits are substantial.

To succeed with agile testing, hire people with the traits of an agile tester and establish a culture that encourages self-organisation and independent thinking. That produces a stable infrastructure without slowing development, higher job satisfaction alongside faster delivery, and the combination of speed and stability that customers expect.

Agile methodology may not suit every project, but its principles can be applied judiciously to any project type. If you're interested in exploring how to deliver quality at speed, schedule a call with one of our specialists.

Keep learning

QA testing: process and best practices
What is exploratory testing?
Effective QA test planning: a framework and guide
What is continuous testing?