UAT: Manual Testing or Test Automation

Imagine you're working on a new app, and it's almost time to hand it over to the users for feedback. Everyone’s been working tirelessly on the development, and now it’s time for the real test: user acceptance testing. This stage is crucial—it’s where your app’s success or failure begins to take shape. But here's the catch: how do you ensure that all the features meet user expectations? Do you rely on a human tester, or do you let automation take the wheel? This age-old debate between manual and automated testing is one that many developers, testers, and product managers face, and it’s no small decision. 

This article explores both approaches, breaking down when it’s best to use manual testing, and when test automation might be better for your UAT process.

What is UAT?

User acceptance testing (UAT) is a critical phase in the software development lifecycle. UAT is a subset of acceptance testing, a process where the end users or stakeholders test the final developed product to ensure it meets their needs and business requirements. 

Before diving into the different testing methods, understanding what UAT includes is important. User acceptance testing usually is the final step before a product is deployed. Testing is performed by the stakeholders or end users who validate that the software works as expected in real-world scenarios. User acceptance testing is different from system testing or functional testing which is usually performed by developers or testing teams in the earlier stages of the software development life cycle. Functional testing focuses on validating that the software functions as expected and meets its functional requirements, while UAT is about making sure that software meets the user’s needs and requirements. 

Manual testing for UAT: The human touch

Manual testing in UAT means that testers (often actual users or stakeholders) execute test cases without the assistance of automation tools. This approach allows for human intuition, flexibility, and context-driven feedback.

Advantages of using manual testing for UAT

• Flexibility. Testers can quickly adapt to new changes. If new changes or features are introduced during the UAT phase, manual testing can easily adjust to these changes without the need to rewrite automation tests.
• Real-world context. Testers can simulate real user behaviors and conduct manual testing that could be difficult to automate. For example, they can perform exploratory testing for the interface, find usability issues, and evaluate the overall user experience.
• Low initial investment. Manual testing doesn't require an initial investment in automation tools or scripting, it is a more accessible approach for smaller teams or projects with limited budgets.
• Critical thinking. Manual testers can take a better look at user experience, considering different factors like user interface, design, ease of use, and other elements that could be difficult to detect in automated testing.

Disadvantages of using manual testing for UAT

• Human error. Some issues can be overlooked by the most experienced testers, particularly when faced with repetitive tasks or a high volume of tests.
• Time consuming. Executing test cases for large applications can take a lot of time, especially when they have to be run for multiple scenarios
• Scalability. As the application evolves, manual testing may struggle to scale. Large teams and more complex systems could require more testers and time, which can impede the speed of UAT.
• Lack of reusability. When manual tests are completed, they can't be reused for future releases or projects unless manual testing teams execute them again. This can lead to inefficiency for projects with frequent updates.

Test automation for UAT: The efficiency factor

Test automation involves using tools and scripts to run previously predefined tests. It includes automating repetitive and complex tasks that would otherwise be done manually during the software testing process. For UAT, test automation can help quickly validate functionality, performance, and even some parts of user experience. Here are some advantages and disadvantages of using test automation in UAT:

Advantages of using test automation for UAT

• Efficiency. Test automation can execute a large number of test cases quickly compared to the time it would take manually. This becomes very valuable when testing repetitive scenarios or large datasets.
• No human error. Test automation is consistent without the risk of human error. This means that software is tested thoroughly without variations in execution.
• Reusability. Automated tests can be reused across different versions or releases of the software, making them a valuable long-term investment. When the test automation setup is completed it can be run every time the software changes.
• Faster feedback. Test automation allows for quicker identification of issues, especially in continuous integration and continuous delivery (CI/CD) pipelines. This is beneficial in agile or iterative development environments where UAT feedback needs to be fast.
• Parallel execution. Test automation allows for tests to be run in parallel across different environments. This significantly reduces the time of the testing phase.
• Test coverage. Test automation can cover more scenarios than manual testing, increasing the depth and breadth of test coverage.

Disadvantages of using test automation for UAT

• High initial setup cost. Developing and implementing test automation requires a significant initial investment of time and effort, especially if the necessary tools and infrastructure are not available. Writing test automation scripts, maintaining them, and making sure that they stay relevant as the software evolves can be a very costly process.
• Limited flexibility. Test automation is great for repetitive and predefined tasks but it falls short with testing scenarios that are dynamic, unpredictable, context-dependent, or require a human touch. UAT often involves testing new features that may not have clearly defined outcomes, making them hard to automate.
• Requires specialized skills. Test automation requires testers with knowledge of scripting/programming languages and experience with test automation frameworks and tools. With a lack of skills, test automation can become a burden rather than a help.
• Complexity in handling UI/UX issues. Test automation typically focuses on functional validation and is not well-suited for exploratory testing which involves human intuition and creativity. For example, a test automation script can validate if a button is clickable but can’t evaluate user interface design or overall user experience.

Combining manual testing and test automation for UAT

The hybrid approach to testing combines the strengths of both manual testing and test automation, allowing teams to leverage the best of both worlds. While automation can handle repetitive, time-consuming tasks efficiently, manual testing is often required for scenarios where human intuition, exploratory testing, or subjective assessment (such as UX/UI evaluations) is needed. Many teams find that a hybrid approach works best for UAT. Here’s how to combine both strategies:

Repetitive scenarios 

Test automation should be used for repetitive test cases such as logging in, performing basic CRUD (create, read, update, delete) operations, or validating system integrations. These tests can be executed very quickly and efficiently, leaving manual testers free to focus on more critical areas.

Critical user scenarios 

Manual testing should be used for critical user scenarios, especially those that require subjective judgment, such as testing user interfaces, workflows, and overall user experience. End users can provide the human insight necessary to ensure that the application meets business requirements.

Continuous automation 

As the project progresses, consider continuously adding automated tests for new features, ensuring that any changes to the application are covered by tests in future UAT cycles.

Exploratory testing 

Allow testers to explore the application, looking for unexpected bugs or usability issues that automated tests might miss. Exploratory testing is where manual testing shines, as it can mimic real-world usage scenarios that automation might not cover.

Conclusion

Whether to choose manual testing or test automation for UAT depends largely on the nature of the application, the size of the team, the project timeline, and the complexity of the business requirements. Manual testing excels when human judgment, intuition, and flexibility are needed. On the other hand, test automation is perfect for scenarios requiring speed, accuracy, and repeatability.

In most cases, a hybrid approach combining both manual and automated testing provides the best results, enabling teams to leverage the strengths of both methods while mitigating their weaknesses. Ultimately, the goal of UAT is to ensure that the software meets the end users’ needs, regardless of whether you choose manual testing, automation, or a blend of both.