Manual Testing vs. Test Automation: A Practical Guide on Choosing the Right Approach

Software tester performing software testing on two laptops and one desktop

In software development, the debate between manual testing and test automation continues to be a focal point. Both approaches have their pros and cons, and choosing the right method can significantly impact the quality and speed of software delivery. This guide will delve into what manual testing and test automation are, providing practical insights on when to use each. By the end, you will have a clearer understanding of how to strike the right balance between these two essential testing methods.

What is manual testing?

Manual testing is a process where testers manually execute test cases without using any automation tools. This approach requires a tester to assume the role of an end user, meticulously exploring the software to identify any unexpected behavior or bugs. It is a fundamental part of the software development lifecycle, ensuring that the software is user-friendly and free of bugs before it reaches end users, taking into account the software's functionality, usability, and performance.

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Key characteristics of manual testing

  • Human observation. Relies on the tester's cognitive abilities to detect issues that might be missed by automated scripts.
  • Flexibility. Allows testers to quickly adapt to changes and explore new areas without the need for script updates.
  • User experience focus. Essential for evaluating the usability and overall feel of the application from a real user's perspective.
QA engineer performing manual testing

How does manual testing work?

Manual testing involves several steps that require careful planning and execution. Here's a typical workflow:

Step 1: Understand client requirements

Understand the client’s requirements, including what needs to be tested and expected outcomes. Familiarize yourself with the software's functional and non-functional requirements and create a team of qualified manual QA engineers.

Step 2: Prepare a test plan

Write a test plan detailing the project's scope, testing objectives, required resources, and suitable testing techniques, tools, and environments.

Step 3: Design the test cases

Develop detailed test cases based on requirements, covering various scenarios and functionalities. Include preconditions, execution steps, expected results, and postconditions.

Step 4: Set up test environment

Prepare the testing environment by installing the software, configuring necessary settings, and ensuring access to relevant data and resources.

Step 5: Execute tests

Execute test cases by interacting with the application as an end user would, following the steps outlined in each case.

Step 6: Report defects

Document and report any defects or bugs, providing details such as steps to reproduce, actual results, expected results, and severity.

Step 7: Track defects

Log reported defects into a bug tracking tool, assigning priorities and statuses.

Step 8: Perform regression testing

Conduct regression testing following best practices after bugs are fixed to ensure no new issues are introduced and existing functionality is intact.

Step 9: Prepare test closure reports

Evaluate test results against criteria to determine if objectives are met. Prepare a test summary report documenting activities, results, and outstanding issues.

Step 10: Gather feedback and suggest improvements

Provide feedback to stakeholders on software quality and suggest improvements for future iterations.

What is test automation?

Test automation is the process of using specialized software tools, like Jenkins, CircleCI, Travis-CI, GitLab CI/CD, GitHub Actions, Bamboo, and Azure Pipelines, just to name a few, to execute pre-scripted tests on a software application before it is released into production. These tools can run tests repeatedly at any time of day, enhancing the efficiency, effectiveness, and coverage of the testing process. 

Automation helps in quickly identifying defects, ensuring that new features or changes do not break existing functionality (regression testing), and improving the overall quality of the software. It is particularly valuable for large-scale projects where manual testing would be too time-consuming and prone to human error.

Key characteristics of test automation

  • Scripted execution. Automated tests are based on scripts that follow predefined steps, ensuring consistency and repeatability.
  • High efficiency. Can run tests at a much faster pace than manual testing, especially beneficial for large-scale regression testing.
  • Scalability. Easily handles large volumes of test cases and complex testing scenarios.
Lines of code

How does test automation work?

The process of test automation can be broken down into the following steps:

Step 1: Select the right tool

Choose an automation tool that fits the project's requirements, such as Selenium, QTP, or Jenkins.

Step 2: Set up a test automation framework

Set up a structured test automation framework for writing and managing test scripts.

Step 3: Create a test script

Develop test scripts using automation tools, detailing the steps and including assertions for expected outcomes.

Step 4: Perform automated testing

Execute the test scripts automatically with the tool, simulating user actions like clicking buttons and entering text.

Step 5: Gather results

Compare actual results with expected outcomes, logging any deviations as defects.

Step 6: Prepare test closure reports

Document the test results, including passed and failed tests, to provide insights into application quality.

Step 7: Integrate automation testing into CI/CD pipeline

Integrate automation testing into your CI/CD pipeline to automatically trigger tests with every code change, ensuring thorough testing before deployment.

Step 8: Regularly update test scripts

Maintain and update test scripts to reflect changes in the application, such as new features or UI updates.

Manual testing vs. automated testing: Key differences

Understanding the key differences between manual and automated testing can help in making informed decisions about which method to use in various scenarios.

Criteria Manual Testing Automated Testing
Accuracy Prone to human error, but essential for scenarios requiring subjective assessment. Highly accurate for repetitive and well-defined tasks, reducing the risk of oversight.
Scalability Time-consuming and less efficient for large-scale testing. Faster, as scripts can run 24/7 without human supervision and more suitable for large-scale testing.
Turnaround time Longer due to the need for human intervention at every step. Faster execution of test cycles.
Cost efficiency Higher long-term costs due to the need for skilled testers. Higher initial investment but lower long-term costs through reusability of scripts.
User experience Better choice for assessing usability and user experience. Limited in evaluating subjective aspects like user interface aesthetics.
Specialization areas Best for exploratory, usability, and ad-hoc testing. Best for regression, load, and performance testing.
Skill requirements Requires understanding of user behavior and test planning. Requires programming and scripting skills.

Why use automation testing over manual testing?

Automation testing offers several advantages over manual testing, particularly in scenarios that demand efficiency and precision.

Advantages of automation testing

  • Speed and efficiency. Automated tests can be executed much faster than manual tests, which is particularly beneficial for large test suites and repetitive tasks.
  • Reusability of test scripts. Once written, automated test scripts can be reused across different versions of the application, saving time in the long run.
  • Accuracy and consistency. Automated tests eliminate the risk of human error, ensuring consistent execution of test cases every time they run.
  • Cost-effective in the long run. Although initial setup can be expensive and time-consuming, automated testing can be more cost-effective over time, especially for regression testing.
  • Continuous integration/continuous deployment (CI/CD). Automated testing integrates seamlessly into CI/CD pipelines, allowing for immediate feedback on code changes and enabling more frequent releases with confidence.

Typical use cases for automated testing

Regression testing 

Automation is ideal for repetitive tests that need to be executed frequently, such as regression testing. Automated tests ensure that existing functionality remains intact after code changes, following best practices.

Smoke testing 

Automated smoke tests can quickly validate the basic functionality of an application after each build or deployment, helping catch critical issues early.

Integration testing 

Automation can simulate interactions between various components of a system, verifying that they work together as expected.

Load and performance testing

Automated tools can simulate a large number of users accessing the system simultaneously, identifying performance bottlenecks and scalability issues.

Cross-browser and cross-platform testing

Automation allows for testing across different browsers, operating systems, and devices, ensuring consistent behavior across diverse environments.

Data-driven testing

Automation testing can efficiently handle tests that require multiple data sets, iterating through various inputs and expected outcomes.

Why use manual testing over automated testing?

Despite the many advantages of automation, manual testing remains irreplaceable in several key areas.

Advantages of manual testing

  • Human intuition and insight. Manual testing allows for the tester’s intuition, creativity, and insight to come into play, which is crucial for identifying user interface issues, user experience problems, and other subtle bugs that automated scripts might miss.
  • Flexibility. Testers can easily modify test cases on the fly, adapt to new changes quickly, and test new functionalities without the need to write or update scripts.
  • Short-term projects. For projects with a short life cycle, manual testing is more cost-effective as the overhead of setting up automated tests may not be justified.

Typical use cases for manual testing

Exploratory testing 

Manual testing is best suited for exploratory testing, where testers explore the application freely to discover unexpected behavior, usability issues, and edge cases.

Usability testing

Human testers can provide valuable feedback on the user interface, user experience, and overall usability of the application, which may be challenging to automate.

Ad-hoc testing 

Manual testing is effective for unplanned, ad-hoc testing, in which testers spontaneously execute tests based on their intuition, experience, and domain knowledge.

User acceptance testing (UAT) 

UAT involves end-users testing the application to ensure it meets their requirements and expectations. Manual testing allows users to validate the software from their perspective.

Exploratory testing of new features 

Manual testing is useful for exploring newly developed features or functionalities that may not yet be suitable for automation.

User interaction testing 

Testing scenarios that involve complex user interactions, such as testing user workflows, user feedback mechanisms, or accessibility features, are often better performed manually.

Edge case testing 

Manual testing is essential for identifying and testing edge cases, uncommon scenarios, and scenarios that require human judgment and creativity to assess.

The bottom line

Choosing between manual testing and test automation depends on various factors, including project requirements, budget, timeline, and the complexity of the application. Both approaches have their unique strengths and are often used in conjunction to achieve comprehensive test coverage and high-quality software.

To strike the right balance, organizations should assess their specific needs and apply a combination of manual and automated testing strategies. This hybrid approach ensures that the application is thoroughly tested, delivering a robust and user-friendly product to the market.

Are you looking to boost your software testing efforts but can’t choose between manual testing or test automation? We can help you decide on the right approach based on your project needs. Get in touch and let’s discuss your project.

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