Test Automation vs Manual Testing: When to Use Them

Software testing is one of the key phases in the software development lifecycle (SDLC) whose aim is to verify that the development team built the software right (according to the specification) and to validate that the designed software meets the customer requirements. Software quality assurance is a huge domain that covers a broad range of techniques, methodologies, and tools. So, even though the major purpose of QA is unified, it is important to divide this process into more specific domains like manual vs. automation testing.

They both have their pros and cons and can benefit any software development project if appropriately applied. But what is the difference between manual and automation testing in particular? In this article, we are going to look into how manual and automation testing work, what their advantages and disadvantages are, and when it is better to opt for either of them.

Manual testing: When to test software manually

Manual software testing is one of the two main forms of testing, under which test cases are executed without any automation tools or scripts. Manual testers verify that software functionality and design are correct by preparing test plans, developing test cases, implementing them manually, and preparing reports upon test case execution. As a result, they identify visible and hidden software defects – discrepancies between expected and actual outputs. And although there are a number of scenarios when manual testing suits the situation more, answering which is better automation testing or manual testing, many would say that automation is way more advantageous and universally appropriate. In their opinion, the days when automation will replace manual testing are coming.

In fact, using automated testing tools is preferable not for every application development project or testing team. Manual testing in QA will never go away, and here is why.

Advantages of manual testing

Each and every company performing automated testing still does some amount of manual testing in place. These are the most compelling reasons why it is so now and why such a state of things won’t change in the nearest future.

Speed and flexibility. Modern teams must be agile. Working in an agile environment, an IT team has higher success rates in their software development, as well as improved quality and speed to market, boosted motivation and productivity. However, at the same time, one needs the capacity to respond to the slightest requirement changes immediately.

Luckily, manual testing offers the flexibility to adapt quickly to nearly any emergencies. If a new feature has to be tested fast or there are changes in the user interface that must be checked, manual testing is a go-to. Besides, one doesn’t have to invest in any specialized tools. All one needs to do is to involve several current members of a team in testing or hire some manual testers who will perform the quality check. This won’t require large upfront costs and will make it easier to manage the budget.
Human feedback. Automated tests can be erroneous. It is common knowledge that the application’s code can contain bugs, but the test automation code can be imperfect, too. As a result, if a QA automation engineer writes tests with bugs, then the team will get false positives in return.

This is why manual software testing is perfect for initial development stages. Errors in automated tests and scripts in the early stages can cause major problems for not only customers but also for a development team. The human element that is inherent in manual testing helps ensure that the testing process is in itself accurate. Testers interact with software as actual users. This way, they are more likely to discover critical usability and UI issues. Broadly speaking, manual testing requires human interaction and communication is invariably beneficial for any project.
Visual feedback. Manual testing allows ensuring that the visual presentation layer translates the commands received from the application layer as expected. That makes manual test operations ideal for UI acceptance testing. They are a better fit when one needs to test visual aspects of a page, how it looks after some action is taken, and whether these visual changes feel confusing or not.

Automated tests cannot imitate the real-life environment in which the app is going to be used precisely enough to detect defects in visual details. Bugs and flaws related to app UI and usability can be better highlighted by a human who then is capable of giving fast and accurate feedback on what they’ve seen. No script of automated test code will provide just as precise and relevant assessment of how the user interface looks and feels.

Drawbacks of manual software testing

Of course, manual testing is not something that works across the board. It proves unequal to some tasks, and these are the most common manual testing disadvantages every team has to be aware of:

Higher chance of errors - Manual testing is not as accurate as automated. The human touch that empowers it to complete UI acceptance testing successfully at the same time makes it less reliable at times and more prone to error. As a result, some bugs may remain undetected and therefore affect end-user experience. It is especially the case with tests that are repetitive. They are more time-consuming and thus difficult to perform manually. If one notices there are such tests on the project, then it’s time to automate. Otherwise, the team can quickly find themselves in a dangerous place.
Time-consuming nature of the process - Although the development of automated tests takes up a lot of time and human resources and requires substantial investment at the initial phase, manual testing can turn out resource-consuming throughout the whole project’s existence. The reason is that costs will entirely depend on the human resources deployed in testing, and the amount of time needed for testing can come out to be greater than expected. However, even though manual testing is more time-consuming than automation testing and more expensive in the long run, it is still more cost-effective in terms of initial investments.
Testing limitations - There are a number of technical limitations that can interfere with the manual testing workflow. And thus, despite that manual testing involves human observation, instrumental in providing user-friendliness and enhanced user experience, it is not suitable for quite a number of essential testing types. This is especially true for non-functional types, like load, performance, and stress testing – the tasks that are too challenging to be executed manually. On the other hand, there are also such test scenarios that are too intricate or absolutely impossible to automate.

Manual testing is best suited for

Exploratory testing. Exploring new product features from different perspectives is only possible as part of the manual testing approach. It allows inspecting a broader range of paths, thus detecting defects that would be otherwise missed by scripts.

Exploration is a manual process. Any member of a project team can contribute to it, as no specialized test automation knowledge is required, but opinions of different team members are welcomed. New features that are still under development and are continually evolving and changing need testing, but at that point, automated testing is not yet viable. So, to be on the safe side, they must be subject to exploratory testing instead.
Usability testing. There are many types of manual testing. Some of them are entirely manual, others can also be automated. Testing products for usability is something that can potentially be automated but is more effective when executed by a human. Usability testing increases one’s chances for the product to perform the way users expect.

To ensure app usability and identify risk factors that limit it, a team has to set up an effective testing plan with clear-cut usability goals, tasks, metrics, and the roles involved in a usability test. The absence of frustration is the main criterion that helps decide if a product is usable or not. And this is a somewhat subjective evaluation that must be followed by specific recommendations for usability problems resolution.
Ad-hoc testing. Ad-hoc testing can only be performed by a manual tester. Its advantage is that it can be done at any point in a QA process and needs no documents or planning.

Unlike automated testing that tests only what is predictable and proves software works as expected due to the joint effort of automated test developers, manual ad hoc testing is useful in another way. It allows a tester to act as a real-life user who can discover defects through error guessing. If applied individually, ad hoc testing won’t be enough for software quality assurance, but it will add support to other QA activities. Sometimes, this method can be mixed up with exploratory testing. The former, however, has a more informal nature and focuses more on negative testing.
Short-term projects. It is not a good idea to start automating tests when the project is planned as a temporary endeavor. Manual testing will be enough to meet the basic needs of such a project. This may lead to wasted resources, and the automation will turn out useless. Automation means higher maintenance and management costs, as well as added person-hours, script-writing, and -rewriting, which will probably not balance out the potential ROI on a small project.

Test automation: How and why automate efforts

Software test automation is the type of testing that is executed using automation tools and scripts. So, to get into automation testing, a QA engineer must be able to use programming tools for writing pre-scripted automation tests. Test automation software is preferable to introduce in a project in a whole bunch of cases since there are problems that manual testing is incapable of dealing with. Stark differences between the two types of testing make people wonder whether automation testing can replace manual testing. There are automation pros and cons to consider before arriving at a clear-cut solution.

Well, what is automation testing in particular? To answer this question, let’s look at the benefits of automated testing over manual testing and its disadvantages.

Benefits of automation testing

Automation is known to increase overall software development efficiency. And there are a number of components that together make up this efficiency.

Cost-effective for large-scale projects. In the long run, automated testing is more cost-effective compared to manual testing. And although it usually requires a higher initial investment, the ROI will be much more gratifying for all the stakeholders in the long perspective.

As we’ve already mentioned, the relatively high start-up investment is needed for the development of automated testing tools that will have to be used repeatedly over a long period of time in the future. This makes the hiring of automation QA engineers for the project a large high-cost component. It is so in no small way because the knowledge of programming languages is a must for the creation of scripts, and thus the threshold to become an automation tester is higher in terms of skills. But if the management sizes up the projects wisely, no money will be wasted.
Better software testing coverage. Since it is performed by tools and scripts, automated testing provides more accurate and reliable results, allows for much better resource allocation, and offers broader testing coverage.

The scope of automated tests is broadened and deepened due to the use of test automation tools. These tools allow running tests on multiple versions of an application (like mobile, web, and desktop applications) and on various computers with different configurations. Automated scripts unattendedly execute thousands of different complex test cases during every test run, which provides testing coverage otherwise impossible with any manual testing technique. Thus, automated testing can help find more bugs compared to human testers, and therefore it is considered more robust and versatile.
Faster result delivery and easier reporting. As automated testing is executed by software tools, it ends up being significantly faster than manual testing. The tools can also record test sessions for them to be reused for other scenarios. For example, automation is great for testing application functionality where the same functions have to be validated with a lot of different inputs and large data sets, such as login or search queries. It all provides for a faster and more efficient testing process and much higher productivity in an organization. Thus, a product can be tested overnight, and the automatically generated testing reports can be emailed directly to you afterward.

However, it must be emphasized that for that timed to be saved through automation. The team must take some effort first and develop those scripts that would aid the process latter on.

Disadvantages of test automation

The automation process is to be designed in a way to benefit the whole QA workflow. However, there are certain challenges that one has to keep in mind and be ready to handle accordingly.

Expensive for small projects - The standard expectation is that a project will have complete test coverage for automation scripts. But every test automation tool has its limitations that can reduce the scope of automation. So, for this expectation to be well managed, one has to avoid overestimating what can be automated by a project team. The tools that are used to run automation testing are also oftentimes expensive, which may, in turn, substantially increase the cost of testing on the project.

Continuous maintenance is obligatory in a repeatedly changed application. As a consequence, the automation test maintenance and debugging of the complicated test scripts will incur additional business expenses as well. And finally, the learning curve for automation tools and the application to be tested is also steep, which is another reason to recalculate one’s potential automation ROI. That said, the cost-effectiveness of test automation on the project is not something that one will get immediately. It takes time and effort to arrive at that point, which is not an option for small projects.
A lack of human expertise - Human expertise is invaluable in terms of feedback about product usability and UI convenience. But human observation is not necessarily entailed, and so, user-friendliness and positive customer experience are more difficult to guarantee. When performing test automation, very little human intervention is required. As a result, it becomes more problematic to get insight into the visual aspects of the user interface. The test script can only act as it is configured. Therefore, sometimes, it can omit errors that would be obvious to a manual tester. A lack of human consideration can lead to a lack of user-friendliness and sufficient user-experience evaluation.

Automation is best suited for

Regression testing. It is a good idea to automate regression testing effort for checking whether preexisting app functions still work correctly after being carried forward to new app versions.

The best time for a QA team to proceed with scripting tests for automation regression testing is when there are modules that can be considered stable, and some bugs are found there repeatedly. However, be advised that those functions must not be changing, and only after you are positive about that, automate. So, once it is ensured that automation is needed, automated regression testing comes into play and a QA team can expect to enjoy the advantages that follow. These may include an increase in the test coverage, test results being continuously updated, improved test efficiency due to fast test execution, and reusability of regression tests. Thus, the automation of tests performed against preexisting functionality will be extensive, but it won’t be deep. That, in turn, can also be an advantage, especially in the face of limited resources.
Performance testing. App testing aimed to measure the system’s behavior and performance under load must be supported by automation tools. For instance, the required simulation of any number of concurrent users has to be automated, as there are no viable manual alternatives to be used instead.

A QA team can design load-test scenarios and develop corresponding test scripts to simulate end-user behavior, scale the load to thousands of concurrent users, and check how an application works under load. There is an array of performance testing tools that can be used to automate UI or API load tests, improving their speed and accuracy. Meanwhile, a test engineer doesn’t have to sit there with a stopwatch anymore but instead can engage in more creative and intellectually challenging tasks.
Repeatable functional test cases. The possibility to spare manual testers from repeatedly performing the same tests lies at the core of automation’s cost-effectiveness. This helps optimize the software quality assurance process and eliminate the monotony of repetitious testing.

Mundane, repetitive functional tests must not be performed manually. They will otherwise take lots of time and serve as a source of many errors. If a task is relatively unchanging from one test cycle to another, then those same monotonous steps should be taken by the script. Then, no tester fatigue will get in the way of automatically correctly validated test results.
Testing what manual testing cannot accomplish. The complexity of modern software systems is increasing exponentially. So, there are more and more scenarios when there is no manual testing technique that could help ensure the quality of a particular aspect of a system. Types of testing that cannot be performed manually include code coverage analysis, memory leak detection, and other types of security testing.

Best automation testing tools

Automation QA testing tools determine how effective the quality assurance optimization process will be. So, as the software testing automation domain expands, the number of tools that are meant to address the emerged challenges grows, too. Here is a list of automated testing tools in software engineering that are most frequently used nowadays:

1. Selenium. This is the number one automation testing tool that nearly every AQA engineer has worked with at some point in their career. Selenium is valued for its flexibility to choose the language, system environment, and browser when executing UI automation testing of web applications.

2. Cucumber. Cucumber is a free BDD (behavior-driven development) framework for testing web-based applications. It provides support for establishing a productive conversation between all project members and helps keep a test automation process organized so that everyone could understand the intended behavior of the software to be developed.

3. Appium. It is a free mobile UI test automation framework used for testing native, hybrid, and mobile web applications. Appium is compatible with all popular programming languages and uses Selenium WebDriver to interact with mobile apps.

4. Unified Functional Testing. Micro Focus UFT One is a tool for automating functional testing. It provides an integrated dev environment that leverages a broad ecosystem of integrations and thus streamlines testing processes.

5. Katalon Studio. This comprehensive automation solution allows for API, web, mobile, and desktop application testing. Supported by Selenium and Appium engines, Katalon Studio provides an integrated environment for convenient UI test automation.

Conclusion

The possibility to apply both manual testing and automated testing to ensure the quality of the developed software is the luxury that cannot be ignored. And if manual software testing is a crucial part of any QA strategy, the use of test automation techniques will benefit your software development project even more. The choice of tools is immense, and the testing team can be as creative and inventive when developing their testing tech stack as they like.

There are a time and a place for both methods of testing. Manual testing helps understand the problem as a whole and explore it from different perspectives. Automated testing helps save time and empower the software test strategy. Finding a happy medium between the two approaches is exciting, and we at Vilmate know how to determine when and where to leverage each method to deliver the best results. If you have a project on your mind that needs a strong team of QA engineers, contact us, and we will do our best to ensure your product’s quality in the long run!