‍Both automated and manual testing are necessary components of a healthy software delivery process. When used together they can provide a comprehensive testing strategy that ensures the best possible product quality.

Automated testing allows for rapid and efficient (re)testing of the same test case multiple times - what is called "regression testing"

Manual testing provides a level of flexibility and attention to detail that automated testing can’t.

In this blog post, I will try to elaborate why test automation can’t replace manual testing.

What is Automated and Manual Testing?

Automated testing can be defined as the use of some tools to execute tests and validate the outputs of the program. As I mentioned already, it is typically used for regression testing, where the same test scenarios (inputs sequence) are run multiple times to ensure that the application behaves the same way each time. When done right, automated testing is highly efficient and can even be used to test complex scenarios that would be difficult or time-consuming to test manually.

Manual testing is the process of evaluating and experimenting with the software, usually done to ensure that it meets the requirements.

It often involves a human tester exercising the software while making observations and offering assessments and results verification. As one can imagine, such testing provides more flexibility than automated testing and allows the tester to explore different paths and scenarios that may not be covered by automated tests.

Benefits of Automated Testing

Automated testing has several advantages over manual testing. Let's explore them one by one

Consistent feedback speed

Automated tests usually provide quality feedback in a matter of hours or even minutes. While some would argue that this kind of feedback is hardly complete, that's not always the point. Having incomplete feedback fast quite often is better than having complete feedback after several days.

Automated tests can also be run in parallel, which means that multiple tests can be executed at the same time. This can greatly reduce the amount of time it takes to run tests, increasing feedback speed even more.

Repeatability

Every automated test run is essentially a copy of the previous run. In the overwhelming majority of cases, tests will exercise the same input and expect the same output. While being susceptible to pesticide paradox, it is still a great and fast alternative to manual regression testing.

Increased reach

Automated tests can also be used to test complex scenarios that may be difficult to test manually.

Automated tests can also be run in different environments, such as different operating systems or browsers. This can help ensure that the application works properly in different environments.

Benefits of Manual Testing

Manual (or some would prefer term "human-driver") testing has several advantages over automated testing.

Flexibility

Manual tests can be more flexible and would usually allow the tester to explore different paths and scenarios that may not be covered by automated tests. Thus, human-driven testing is less susceptible to pesticide paradox.

Initial feedback speed

While automated tests are good for providing fast feedback of repetitive test runs, when you need to exercise a new product or even new functionality within the same product, human-driven testing will provide faster feedback. Writing an automated test framework isn't an easy or fast task, and usually would take days or weeks. On the other hand, it would usually require hours to get some solid feedback when testing manually.

Better feedback

Manual testing also allows the tester to explore different parameters and variables that may be difficult to test with automated tests. When manually exercising the product, a skilled tester can also provide feedback on many non-functional aspects of the application, such as usability. After all, manual tests allow the tester to interact with the application in more natural way.

So Why Test Automation Can’t Replace Manual Testing?

As you hopefully see now, automated tests are more like an extension to manual testing rather than an alternative. Automated tests are extremely helpful for detecting regressions and running test scenarios that are impractical to run manually.

However, that's pretty much everything automated tests have to offer. They are also susceptible to the pesticide paradox - an effect when inputs that are tested would produce correct outputs, while slightly different inputs would not (if you want to learn more about this interesting effect - please drop me a comment - I could as well write about it)

Similarly, any tester would benefit from having test automation (programming) skills, as it will allow them to:

Increase the efficiency of their testing efforts
Make sure both manual and automated tests are used when needed (and only - when needed)

In simpler words, relying on manual testing only isn't an option these days.

Conclusion

Automated and manual testing are both necessary components of software testing, and when used together they can provide a comprehensive testing strategy that ensures the best possible product quality.

When combining automated and manual testing, it’s important to use the right combination of tests. Automated tests should be used for regression testing, where the same tests need to be run multiple times. Manual tests should be used to explore different paths and scenarios that automated tests may miss.

Automated testing can’t completely replace manual testing, since manual tests can be used to explore different paths and scenarios that automated tests may miss. Organizations should use both types of tests in combination to ensure that the application is thoroughly tested and meets quality requirements.

P.S

If you are interested in learning how to properly write a test automation framework feel free to check my paid course on

Also please feel free to check my YouTube channel for more analytical content and programming tutorials: https://www.youtube.com/channel/UCkJRvCK2-l2gCuPT9-HUG7A

Why Test Automation Can't Replace Manual Testing

How Automated and Manual Testing Complement Each Other

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