What is the Automation Testing Pyramid & Why it Matters for Agile Teams?

Testing software is the backbone of any product development, an everyday activity that is crucial to the software's health and customer satisfaction. However, testing can also be time-consuming, expensive, and often challenging to manage.

Enter the Automation Testing Pyramid! 

The Testing Pyramid is a fundamental approach that Agile teams can use to execute efficient testing that aligns with Agile principles. In this blog post, we will explore the Testing Pyramid in-depth, discussing its fundamental principles, benefits and how to implement it in an Agile environment.

Whether you are a developer, tester, or product owner, this post will provide valuable insights and practical tips to improve your software testing practices.

Structuring Tests Using the Test Pyramid Model

With the test automation pyramid, you can effortlessly strike that perfect balance when executing automated tests. Despite its sturdy-looking structure, this pyramid is not a fixed framework and can be adjusted to meet your team's present and projected requirements.

Initially suggested by the creator of Scrum Alliance, Mike Cohn, the test pyramid depicts the prioritisation of test execution, outlining three tiers of automated tests: Unit tests, Service/Integration tests, and End-to-End or UI tests.

Unit tests

At the pyramid's foundation, we find the unit tests, representing the bedrock upon which all other tests depend. They occupy the most significant section of the pyramid and are usually the tests you will create the most of. 

The objective of unit tests is to test a single "unit" within an application, which should not rely on other sections of the system or application. 

When developing unit tests, treat the function as a black box, disregarding its logic. Your concern is only whether the specified input results in the anticipated output. If that unit of code or function is subsequently refactored but the output should remain as it was, your unit test will assure that the function has not regressed and continues to do its job. If a function is redesigned and a new output will be expected, your existing unit tests will need to be refactored as well to set a new expectation.

Integration tests and Service Layer or API tests

Integration testing aims to guarantee that components or units within an application operate as anticipated when integrated with one another. In contrast to unit tests, which must always be independent, integration tests are essentially dependent. 

Their purpose is to validate that the dependencies of components within a system are functioning correctly. The difference between a unit test and an integration test is that unit tests examine elements in isolation, whereas integration tests scrutinise segments of your application working together as intended.

Integration tests can help construct a new application or feature without the UI. However, once the UI is available, it is the perfect time to create end-to-end (E2E) tests.

End to End and UI tests

End-to-End testing is a process that assures us the entire system works collectively and its purpose is to mimic the actions of an actual user with the user interface and all external or 3rd party systems.

For instance, an E2E test might be conducted to mimic the behaviour of a new user, registering a new account, logging in, making a payment, etc.

These tests are at the top of the testing pyramid, examining user experience or interaction with interfaces.

Unit tests are the most isolated elements, whereas E2E and UI tests have the highest level of integration since they examine genuine user interactions within your application.

UI or End-to-End tests can often be the hardest to reliably automate and will usually take the longest to run and for that reason, they will be far fewer in number than your Unit and Integration tests. They are represented in the pyramid with the smallest volume of the overall test count.

Complementary-Read:End To End Testing vs Regression Testing

The Benefits of Using the Testing Pyramid Model for Agile Software Development

The Agile principles like reusability, collaboration, sustainability, scalability, and user-friendliness are key components of any successful technology solution and must be prioritised to reduce time-to-market and boost the quality of the product.

Before releasing any feature, tests must be executed on the unit, integrated and E2E levels to verify that our product functions correctly.

Agile processes are integral to delivering continuous value and developing DevOps practices. Due to the ever-changing nature of Progressive Web Apps and Mobile Apps, quickly refactoring the code, checking cross-platform performance, and releasing frequently without needing to revert to excessive manual testing is crucial. 

Agile delivery approaches are beneficial for measuring performance in each environment, preventing functional regressions, meeting micro-service standards, detecting bugs early and frequently and ensuring ongoing product stability and quality.

The Test Automation Pyramid effectively directs the automated test strategy, enabling all these benefits.

What Does the Future Hold for the Testing Pyramid?

Agile software development relies on the testing pyramid to enhance the overall quality of developed products. The pyramid comprises three levels: unit, integration, and E2E, which capitalise on test automation's strengths and drives essential testing types. This agile test pyramid is instrumental in achieving the following:

Balancing Coverage and Effort 

The test pyramid highlights appropriate balance amongst different but related project testing types, making it critical for teams that tend to wander from project timelines and that might adopt excessive test coverage, particularly with manual or automated UI tests. It also caters to teams that place too much emphasis on regression testing or need a test automation strategy just to get started.

The test pyramid helps drive the ideal proportion of automated tests of different types with the intention of always finding bugs at the earliest available opportunity.

Project Stagnancy Reduction

The structure of a test portfolio strongly influences the efficacy of software delivery. Agile teams, as a rule, carry out continuous planning, tracking, and review. The test pyramid aligns the test automation strategy with the project goals, ensuring the team does not lose sight of its progress.

Aiding Consumer-Driven Contract (CDC) 

CDC testing and acceptance test-driven development (ATDD) methods already incorporate the test pyramid and its levels. Consequently, CDC tests validate the system's core functions and help the in-house team verify customer expectations.

Broader Strategy and Range 

The test pyramid's structure is not rigid, making it adaptable to specific environments, enabling diversity in automated test volumes.

For example, teams can run unit tests for UI and verify that the application functions correctly, reducing the application’s time to market and avoiding costs incurred from fixing production bugs.

Facilitating Team Collaboration 

Agile software development encourages cross-functional teamwork from start to finish. Together, these groups can develop a broader test strategy and continually validate code integrity at multiple levels of the application stack.

Conclusion

In summary, the test automation pyramid serves as a valuable guide for agile teams to develop a comprehensive and effectively layered, test automation strategy. It empowers various stakeholders to take ownership of test automation and keep track of the project's advancement and the product’s quality.

Ultimately, the pyramid lays the groundwork for agile testing success and boosts team productivity and product quality.