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Test Automation vs Manual Testing: Picking the Right Balance

Software testing is an integral part of the development of a successful software project. Software testing itself consists of a…

By Testim,

Software testing is an integral part of the development of a successful software project. Software testing itself consists of a huge domain in which many variants exist. To give you an idea, some examples of test methodologies are regression testing, smoke testing, network testing, integration testing, and many more. 

In addition to the abundance of testing formats, there is also a very active discussion about automated testing is better than manual testing. This post will guide you through the benefits of each approach and will try to conclude the best option for each use case. Let’s start by exploring the difference between manual and automated testing.

What’s the Difference?

In manual testing, a testing engineer (a human) manually executes test cases. This means the testing engineer describes several scenarios and edge cases that they want to verify the functioning of. Manual testing doesn’t use any tools or scripts. This means that the testing engineer has to prepare a dataset and the scenario and trigger the right inputs or actions to test the described scenario.

With automated testing, all of this—as the name suggests—is automated. This means using scripts and tools that prepare data and a state, then execute the steps required to verify the scenario in an automated way.

Both manual and automated testing have benefits and disadvantages. It’s worth knowing the difference, and when to use one or the other for best results.

Pros and Cons of Manual Testing

Let’s compare some of the pros and cons of manual testing.

Benefits of Manual Testing

With manual testing, the testing engineer has total control over executing every action. This means more visual feedback during the process, which allows the testing engineer to debug or find issues more easily. 

Besides that, as manual testing does not require any tools, a company spends less money on testing. However, don’t forget the costs of hiring a larger testing staff to verify that your software product is functioning well. 

Also, for small changes or codebases, it makes more sense to quickly verify a function by manually testing it instead of configuring and spinning up a whole testing suite.

Lastly, manual testing works well for finding visual bugs and testing the user-friendliness of an application. This part of testing involves human observation to find any glitches—something that can’t be (properly) detected by automated tools.

Disadvantages of Manual Testing

Normally, manual testing requires more time to complete. The testing engineer has to prepare data sets, prepare the application state, and execute all steps to verify to complete the scenario. The process is slow and prone to human errors. Just one error can mean that the testing engineer has to do the whole setup all over again.

Many companies believe that manual testing is cheaper because they don’t have to spend funds on test automation tools, or continuous integration (CI) tools. However, these tools are cheap compared with finding and employing multiple testing engineers who actually carry out the same work as automation tools.

Many tests are difficult to simulate with manual testing. Stress testing is a prime example of this. Stress testing tests software under a heavy load. Testing engineers use this type of testing to find an application’s breaking point and experience how it behaves under this high load. Often, stress testing requires the creation of many hundreds or thousands of requests in a short time frame. Sometimes, it requires the use of a bunch of users all connecting at the same moment to the application. It’s just not possible for a testing engineer to recreate this type of behavior manually.

Finally, complex scenarios are often avoided during manual testing or are only tested sporadically. This leaves testing gaps in the application. Automation is a great option for a testing engineer to simulate these complex cases.

Summary

  • The cost of manual testing depends on human resources deployed in testing.
  • Manual testing is often slower and prone to human errors.
  • Manual testing is not suited for many types of testing (like stress testing).
  • It’s hard to test complex cases manually.
  • Manual testing is good for finding visual or UX bugs.

Looking at this list, you should see that manual testing has more disadvantages than benefits, even though it still has its uses. The major misconception with manual testing is that IT leaders think they save money by not using paid automation tools. But they forget about the hidden costs of staffing a larger testing team to fill the gap between manual and automated testing.

Pros and Cons of Automated Testing

Here are some of the advantages and disadvantages of automated testing.

Benefits of Automated Testing

The first thing I want to point out is how resilient automated testing is. Automated testing is reliable and always returns the same result (reproducible). And because every step is automated, it’s not subject to human errors like manual testing is.

Also, it’s logical for a company to invest in test automation tools that help them to set up their testing suite. This enables them to run things like stress testing, as the suite can simulate thousands of clients all connecting at the same moment. In my opinion, an automated test suite allows you to better test and monitor the quality of your product.

Once you have your testing suite installed, it’s easy to hook up other projects to this suite.

Next, test automation allows you to run all your tests much more quickly than manual testing. You can quickly simulate complex scenarios. And unlike staff, your testing suite does not complain when it has to verify these complex cases.

Finally, automated testing enables your developers to receive quicker feedback. It benefits the overall productivity of your development team and gives more insight into the quality of the application.

Disadvantages of Automated Testing

Automated testing can’t be used for detecting visual or UX bugs. Finding UX bugs requires a human eye. Simply running your test suite can’t measure other things, like customer experience. So automated testing tools won’t cover all testing scenarios. Some scenarios just can be automated.

Also, developers might lose valuable time debugging incorrect testing scripts. Often, my code is working perfectly, but I spend more time debugging the automated tests I coded.

Summary

  • Automated testing is more reliable and quicker than manual testing.
  • It increases the development team’s productivity (quicker feedback); however, the team can spend a lot of time debugging tests.
  • Automated testing allows for different, complex types of testing.
  • It improves project quality.
  • It doesn’t find visual or UX bugs.

So you can see that automated testing has a lot of benefits. But it doesn’t do everything. For example, automated testing isn’t fit for finding visual bugs. Also, I have to admit that not everything can be automated. However, automated testing definitely increases the quality of your product.

When to Use Manual Testing

Manual testing is suited for usability testing, ad-hoc testing, and exploratory testing.

Usability testing focuses on measuring an application’s user-friendliness. Ad-hoc testing uses a free approach in which the testing engineer tries to break components without a set scenario. 

The last approach, exploratory testing, focuses on the tester’s knowledge, experience, analytical skills, creativity, and intuition. Here, the test is characterized by poorly written specification documentation or a short time for execution. 

When to Use Automated Testing

Automated testing is good for regression testing, performance testing, load testing, and highly repeatable functional test cases. Automated testing should be an integral part of the DevOps cycle. 

In short, you should automate every test that you can.

The Bottom Line

Testing should be an integral part of software development. There are many factors you should take into account when choosing your testing strategy. The ground rule for testing: try to implement as much automated testing as you can. Manual testing is slow and doesn’t fit into today’s agile practices. The benefits of automated testing are far greater than those of manual testing. That’s why your company should invest in setting up an automated testing suite. Take a look at our guide to help you get started. Good luck!

This post was written by Michiel Mulders. Michiel is a passionate blockchain developer who loves writing technical content. Besides that, he loves learning about marketing, UX psychology, and entrepreneurship. When he’s not writing, he’s probably enjoying a Belgian beer!

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