Manual Testing vs. Automated Testing: Which to Use When

Testing is an integral stage of software development. Testing helps to ensure developers are working per the project specifications and requirements. There are two main testing methods: manual and automated. But which one should you be using? It can be a challenging decision to make, especially considering the amount of time each takes. In this post, I'll talk about the differences between manual and automated testing. I'll also explain how each test works and why and when you should choose one over the other.

What Exactly Are Manual Tests?

Manual testing takes advantage of human input to provide a new perspective on how the software operates. In manual testing, the development team must carry out all actions and the necessary responsibilities including identifying potential errors, generating sufficient input data, analyzing gathered data and evaluating the output. Manual testers have a huge role in ensuring that software is functioning correctly on release.

Manual testing relies on logic and critical thinking skills, which are only improved with practice. The more experience a tester has, the better they are at catching and foreseeing bugs. With higher quality manual testing, testers test a product in its natural environment to find problems that might not be easily noticed. But manual testing is disadvantageous because it often takes longer to complete.

What Exactly Is Automated Testing?

An automated test is a set of instructions run by a software program, either to verify the behavior of the software or to identify bugs in it. Automated testing intends that a computerized test execute all its steps with minimal human intervention once written.

Automated tests are preferred because they are relatively fast and can be run as often as needed without human involvement. Travis CI, for example, runs a computerized test every time a commit is made to a repository.

To perform an automated test efficiently, you need three pieces: an isolated test environment, a test scripting language (such as Python), and an open-source automation framework.

What Is the Difference Between Manual and Automated Testing?

As mentioned, manual testing involves the tester using their own time to test a piece of software by hand. Automated testing leverages tools like programming languages to test the software seamlessly and without human intervention. Below, I have listed some of the significant differences between manual and automated tests.

Time and Cost-Effectiveness

Manual testing may seem cost-effective since it doesn't need several tools; however, if you need to test different components of a system, you may need to hire a lot of testers.

Automated tests use computers to execute tests, making them faster than manual tests. Also, automated testing doesn't require a human to monitor or conduct the whole testing process. Automation helps save on time and money because you don't need to hire people to act as testers.

Additionally, multiple machines can use automated tests. You can write a script once and run it everywhere, especially to test mundane functionality.

Ease of Use

Testing tools and frameworks make using automated tests seamless because they've done a lot of the heavy lifting on the coding process. For example, with Waldo, you get to create automated mobile tests without coding them yourself.

On the other hand, with manual testing, it's paramount for a tester to fully understand the software. This can be daunting to testers who have never interacted with the system. Testers go through a steep learning curve because of the app's complexity.

Reliability

Manual tests are susceptible to errors because humans tend to make mistakes often. The core of manual testing is human involvement. Humans are more likely to make mistakes and thus reduce the accuracy of the test.

On the other hand, automated testing leverages machines, and machines hardly ever make mistakes. Therefore, devices increase the accuracy of automated testing. Automated tests run in parallel and can test different parts of the system; this makes them efficient. Unlike manual tests, automated tests take less time to complete, and the results are consistent, too.

When Should You Use Manual and Automated Testing?

During testing, you may find that the software doesn't conform to the set standards. In such cases, manual testing assesses whether a product meets the requirements specified by a product's system requirements document. Manual testers verify that the software meets its stated functionality by performing functional and nonfunctional tests, whereas automated tests confirm that these conditions are met.

While automated testing is a potent tool for scaling up testing, it has drawbacks. Automation isn't always perfect, and there can be many edge cases that can trip you up. If automated tests give you inaccurate results (or fail to catch bugs), then manual tests might be the alternate option.

One test is not a replacement for the other. Manual tests have their relevance, and so do automated tests. There are areas in which manual tests thrive where automated tests fail. Let's see when to use manual testing vs automated testing.

Usability Testing: Use Manual Testing

As the name implies, usability testing is user-centric. Thus, the best type of test is manual testing. This type of testing looks at how an application is user-friendly and offers a seamless experience. The correct test type is from an actual end user instead of a mocked end user by a machine. The feedback and input from a real user are more accurate than that predicted by the machine.

Ad Hoc Testing: Use Manual Testing

Just as the name suggests, ad hoc tests are informal and have minimal business logic to work with. Ad hoc testing is the process of conducting a test on-site, either in progress or after a software release. Ad hoc testing builds on traditional usability tests such as exploratory testing.

Exploratory Testing: Use Manual Testing

With exploratory testing, the goal is to look for unprecedented scenarios. Now, a machine is limited to that which is known. The best way to conduct exploratory testing is manual because a human tester is well versed and more skilled. The tester leverages their experience and expertise to mock scenarios beyond the scope of what is documented. Here, the human element is essential as it relies on things that a machine lacks, such as intuition.

Regression Testing: Use Automated Testing

Regression testing is a repetitive test. As such, developing a script to test mundane tasks and standard functions is easier. A regression test is a software testing process that checks an application to see if the changes in new versions have destroyed or damaged old functionalities. This type of test can be time-consuming, and thus automating the process may save one from a lot of agonies.

Performance Testing: Use Automated Testing

A performance test aims to measure a system's or application's response time. Now, conducting this test manually can be daunting. For example, you can test how long a database query takes or how many milliseconds it takes to load your homepage. Most testers prefer automated tests, as they offer accurate results with minimal human intervention.

Load Testing: Use Automated Testing

With this type of test, the idea is to simulate a heavy load on the website, which helps developers identify weaknesses in the system and make adjustments before live use. For example, suppose it turns out that a web application doesn't scale well when subjected to a high level of traffic. In that case, the developer might want to consider redesigning its architecture or adding more servers. Only automated tests can provide such simulations effectively.

Which Is Easier: Automated or Manual Testing?

Testers use methods like automated and manual testing to test software applications. They both have their benefits, but which is easier? Automated testing, for the most part, offers faster turnaround times and less labor-intensive work than most manual tests. These tests allow your computer to perform all of the manual testing without the worry of making mistakes. Further, the tests catch and fix bugs quickly which helps build your company's confidence.

When Should You Prefer Manual Testing Over Automated Testing?

The significant difference between manual testing and automated testing is that an actual person does one while a machine does the other. Automated testing is generally much faster and more reliable as a machine does it, whereas manual testing is prone to errors. However, which to use will depend on your test scenario. For example, manual testing is appropriate for usability, ad hoc, and exploratory testing, while regression, load, and performance tests thrive on automation. Manual and automated tests generally complement each other.

To determine when to use manual testing vs automated testing, examine your team's needs and resources. Decide how much time you can spare from your current workload to perform a manual test and how much effort and money you'll need to invest in the automation tests. Automated testing is probably the way to go if you can't spare the time or money that manual testing requires. While at it, have a look at Waldo for a seamless automated mobile testing experience.

This post was written by Mercy Kibet. Mercy is a full-stack developer with a knack for learning and writing about new and intriguing tech stacks.