It's 2022, and automated testing is a staple of software engineering. But that doesn't mean there's a consensus. There are people who still don't think test automation is valuable. And there are those who like the idea of automated testing but struggle to articulate why they think it's important. 

This post was written for people belonging to the latter group, trying to convince people from the former group that automated testing is worth it. I'll share 10 reasons why automated testing is important and why you should use it. These are true regardless of the size of your organization, the industry you're in, or whether you're a start-up or a Fortune 500 company. Let's get started. 

The Main Benefits of Test Automation

Without further ado, here's the list of 10 benefits of test automation. Keep in mind that these are not in any particular order. Also, this list is far from being exhaustive; I could certainly think of more than 10 items to add—and you'll likely be able to think of some benefits yourself after reading the post. 

But the post has to end at some point, and 10 is a nice, round number, so 10 it is. Enjoy! 

1. Speed

Speed is certainly the first thing that comes to my mind when I think about automated testing benefits. It goes without saying that human testers simply can't match the speed of automated tests. 

Why is speed so important? In short, it helps you keep your feedback loops short, allowing for quicker time to market. With the help of automated testing, you can verify your application matches the expected quality in a fraction of the time you'd take with human testers. That means you can release more frequently, delivering value to your customers sooner and more often. 

2. Cost Reduction

The second item on our list is, in certain ways, a direct consequence of the first one. With automated testing, you can test more of your application, at a fraction of the cost. Once you pay the initial investment—i.e., creating the tests—all future executions are virtually free, as far as human resources are concerned. Of course, test execution requires computational resources, but at the end of the day, the investment is worth it. 

3. Test Coverage

When I say "test coverage," I don't mean "code coverage"—as in the percentage of a codebase covered by automated unit tests. Test coverage here refers to a broader concept: the total of areas, concerns, and scenarios of the application that are effectively tested. 

Automated testing can dramatically increase the test coverage of an application because it allows testing scenarios that would be impractical or downright impossible to test manually: 

• Unit testing can help you test logical branches inside the code that would be too hard to exercise via a UI.
• Load testing, endurance testing, and other forms of performance testing allow you to verify how the application reacts when under huge pressure.
• Some forms of synthetic monitoring allow you to simulate the application being accessed by users from different regions of the world to verify whether the app reacts correctly—e.g., regarding internationalization.

The consequence of this is that automated testing leads to higher quality. This is because it enables you to exercise the application in ways you likely wouldn't be able to do manually.

4. Regression Testing

In the context of software quality, "regression" means your application starts behaving in an undesirable way after a change. Maybe a feature stops working when you add a new one. Or a bug getting fixed causes an old one to resurface. We say the application has "regressed" to a previous, undesired state—hence the name. 

Software is, in general, very prone to regression, which means any change to a codebase is potentially dangerous. And the only way to rule out the possibility of regressions would be to comprehensively test the complete application after each and every change, regardless of how seemingly small it is. 

Doing so manually would either elevate your costs dramatically or increase your time to market to unacceptable values. And that's where automated testing comes in handy. With automated testing, it's not only possible but economically feasible to comprehensively test the application after each change. 

5. Reproducible Testing

One of the problems with manual testing is that it can be error prone. Different people might introduce variations in the tests. Over time, these variations can accumulate, resulting in inconsistent and less reliable results. 

With automated testing, it's guaranteed that the test will always be executed the exact same way, as long as it exists. Such reproducibility and consistency result in tests that are more robust and whose results are more reliable. 

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6. Early Detection of Defects

As you've seen, automated testing generally lowers the cost and difficulty of carrying out software tests. When things become easier and cheaper, people do them more often. That's Economics 101. 

If you can test more often, you can and should test earlier. And that's what lots of people and organizations do when leveraging test automation. They move the testing activities to the beginning of their development cycles. That means they're more likely to find defects and problems earlier, which lowers the cost of fixing them. 

7. Lower Opportunity Cost

"Opportunity cost" is a common expression in economics. It basically means that when you're doing something, you're not doing all other possible activities, some of which could yield a higher return on your time than the activity you're doing right now. 

Every time you have people performing activities that can be automated, you're incurring serious opportunity costs. After all, those people could be doing different activities that require human creativity and ingenuity and could lead to more valuable returns. 

When you automate testing—and, broadly speaking, all activities that are possible with automation—you free those people to work on more interesting, potentially more valuable tasks. 

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8. Less Dependency on Specific Team Members

Manual testing processes often require highly specialized knowledge that only a few select members of the team have. To make matters worse, such procedures are likely not documented. The consequence of such a scenario is having a low bus factor—i.e., you're excessively dependent on key people in the organization. 

As you've seen earlier, automated testing enables reproducible, consistent tests. Once you create a test, it will always run correctly, even if you leave the company. 

Thus, automated testing reduces the dependency on key team members, making teams and organizations more robust and anti-fragile. 

9. Executable Documentation

This item is closely related to the previous one. It simply means that automated tests can act as documentation. Unit tests, for instance, can help engineers understand how a given API works, which methods it exposes, and which parameters it expects. Behavior-driven development was explicitly created with the goal of helping people in an organization collaborate on the creation of specifications for applications. 

The set of all your automated tests can act as a comprehensive—and, what's better, always up-to-date—form of documentation that expresses how the application should behave at all times. 

10. Possibility of CI/CD

Continuous integration (CI) and continuous delivery/deployment (CD) are staples of modern software development. They simplify the process of releasing software, making feedback loops shorter and allowing teams to deliver value quicker and more often. Thanks to CI/CD, integration hell is a thing of the past, and deployments have become as boring as they can be. 

And this is the final benefit of automated tests: they pave the way for CI/CD. Having a suite of automated, self-verifiable tests is a must if you want to deploy software as often as the current market expects. You want to move fast and deliver value while at the same time maintaining high quality. With automated testing, you can do both. 

Leverage Test Automation for Fun, Purpose, and Profit

I'd say that, nowadays, most people in the software industry are at least familiar with the notion of test automation. Not everyone "buys" the idea, though, and even people who are amenable to the concept often can't express why they think it's a good idea. 

In this post, I've walked you through 10 reasons why test automation is worth it. Most of them are business reasons, usually having to do with cost reduction. But there are also plenty of human-centric reasons to leverage automated testing. The main one is freeing people to do more meaningful work in activities where their humanity makes a difference. 

This post was written by Carlos Schults. Carlos is a consultant and software engineer with experience in desktop, web, and mobile development. Though his primary language is C#, he has experience with a number of languages and platforms. His main interests include automated testing, version control, and code quality.