Striking a Balance Between Manual and Automated Testing: When Two Is Better Than One

With any kind of business, you need to put effort and resources into building something worthy, something that will justify your investment. And the only way to do that is by providing a superior quality product and flawless experience to your customers.

Quality management is one means for making it possible. It provides the tools and methodological foundation for building a great product.

Software quality is a broad and complex concept. It deals with both the functional and non-functional aspects of a software product. This means that good quality software works as required and has a proper inner structure.

This is typically achieved through a set of practices, such as quality assurance, quality control, and testing. While the first two are more high-level organizational activities dealing with process and result monitoring, testing is a hands-on, practical approach to ensuring the software quality.

Based on the way it is performed, testing is typically divided into manual and automated categories. Below we will explain each in detail and focus on their benefits and drawbacks so you can make an informed decision and choose an approach that fits your needs best.

Manual Testing: true-to-life and flexible or risk-prone and costly approach?

Manual testing is the process of checking a software product against functional and non-functional requirements by hand. It is typically conducted by a quality assurance team.

This means that the testers actually run your app on different devices, and use it exactly as your end users would, in order to find any deviations from the original requirements. The team relies on the predefined test cases to check all features and possible use scenarios and find any errors or flaws with the app’s functionality, UX, and design.

Manual testing usually involves the following activities:

• Requirements analysis. Your testers must know your product in and out to be able to notice the deviations or errors in it. Thus, thoroughly documented specifications come in handy when it comes to manual testing.
• Test cases creation. Based on the functional specifications, the testing team will create a set of test cases for your product. These should cover all major features and design elements within your product, for example forms and fields validation, interactions with the database, upload functionality, filtering, and search results.
• Conducting the tests. Once you have the scenarios and understanding of what you need to check, you can run the tests one by one.
• Logging bug reports. In the process of manual testing, document all existing bugs and errors you find in the app. Clear and detailed logging saves you time and money, as your development team will be able to understand and fix the issues faster.

After the bugs are fixed by the development team, the team will manually verify that the issues are solved and the changes within your app haven’t caused any further errors.

A complex and important part of software development, manual testing has its benefits and drawbacks. The most significant ones are listed below.

The benefits of manual testing

• True-to-life testing

Manual testing allows for the most precise simulation of the real-life environment in which your app will be used. Any bugs or flaws that might occur when a user launches an app are likely to be captured through the process of manual testing.

• Thorough design review

Automatic scripts can’t provide feedback on the app’s look and feel. Getting insight from a real person can be invaluable if you want to be sure your app is easy to use and has pixel-perfect UI.

• Lower short-term investment

With the manual testing process, you don’t have to invest in any special tools. Having several members of your team or hiring additional resources to do the quality check makes it easier to manage the budget and requires no upfront costs.

• Increased flexibility

Work in an agile environment. You need the capacity to react to the slightest requirement changes instantly. In this case, manual testing offers the freedom to adapt to anything. If you want to quickly test a new feature or check any changes in the UI, manual testing is exactly what you need.

The drawbacks of manual testing

• Increased risk of a failure

Depending completely on a human, manual testing might be less accurate and thorough. People are more likely to miss some minor errors and flaws in design. Consequently, human error might occur any time during the manual testing process. Moreover, it makes little sense to run manual tests more than twice: testing fatigue might occur when your QA team already knows the product so well that they no longer can notice new bugs in the product.

• More resources and time required

Manual testing is typically a labor-intensive activity. It is slower than simply running a script, and requires more investment depending completely on human resources. And those expenses will only grow as your product evolves. Additionally, manual tests cannot be reused as automation scripts can be. Every time a new feature is added to your product, you must retest the whole product to make sure this change hasn’t broken anything.

• Not everything can be tested manually

There are several limitations to the manual testing approach. For example, it is difficult to conduct load and performance testing manually, as it requires a great number of users/testers and devices running the program simultaneously. That is why such tasks are best handled through special tools and automation.

Automated testing: time and cost-efficient or limited and shallow method?

Automated testing is defined as a process of executing pre-scripted tests on a software product before it is released into production. When comparing manual vs automated testing, you quickly find that the main difference lies in the way each of the methods is performed. While manual testing is conducted by hand, automated testing relies on the dedicated software tools being used.

Test automation tools are used to execute tests, report the results, and compare them with earlier test runs. Such an approach requires less human participation, allowing for multiple test reruns at any time. Other than that, the method has the following pros and cons.

The pros of test automation

• Quick and effective

Executed by special software tools, automated testing requires significantly less time and effort. Once set up, the testing framework does all the work autonomously, allowing for test reuse. The tests can run simultaneously on various machines and browsers, which reduces the testing time and effort. Automated testing is also considered more thorough as it is unbiased and relies solely on algorithms.

• Better long-term ROI

While requiring some upfront investment (although there are some free open-source tools you could use as well), automation proves to be more cost-efficient in the long run. Having introduced an automation framework once, all you have to do is add more test cases as your product grows. Also, if you need to run your tests repeatedly, automation can save time and money for your team, while still introducing reliable results.

• Transparent and meticulous

In the manual process, only the tester can see immediate results. The QA automation process is handled with the help of dedicated tools, which allow for better transparency. Everyone within your team can sign into the system and see the results of the testing in real time. This contributes to better collaboration and visibility within your team. Plus, as mentioned above, automated testing allows you to test every single detail within your app, even those that cannot be tested manually.

The cons of automated testing

• Additional costs required

Whether it is a third-party tool you will be using or a custom automation framework, additional investment will be required to set up a proper testing process. Although, you benefit in the long run from reusing the tools you buy or the framework you build, you still should consider these initial expenses. Additionally, as any software tool, your framework will require continuous maintenance to function properly.

• Lack of human input on usability and UI

The machine won’t provide an unbiased opinion on your app’s UX or design. It will just check every element in your product against the parameters you set. To make sure your app is easy to interact with and has a good look and feel, you will still need to employ actual user testing. Automation proves to be useful only for verifying the functional and technical aspects of your product.

• Tools’ limitations and in-built issues

Third-party automation tools often don’t have the range you need to test your product thoroughly. While you might extend them and customize according to your requirements, it is still a drawback to consider. Moreover, as any software product, such a tool can have bugs and issues of its own. If not detected early, this might have a negative impact on your testing process as well.

Manual vs automated testing: Which one works best for you?

Being a vital aspect of the product success, software quality is often overlooked or completely ignored. Just think about it. If you ever considered software development for your business, you probably think about features to add, tech stack, or design solutions you might use in the first place. The chances are you haven’t thought about specific testing methods to use.

This, however, might lead to unfortunate consequences, resulting in failed projects and billions of dollars cast to the wind.

While there are more software testing techniques and methods, automated and manual approaches are the two options causing most confusion. Which one would be perfect for you depends largely on the type of your product.

Manual testing–a go-to method for short-term projects, minor changes, GUI-oriented products

"It only makes sense to use automated testing tools when the costs of acquiring the tool and building and maintaining the tests is less than the efficiency gained from the effort."

John Overbaugh, a senior SDET lead at Microsoft (Source)

If you build a simple website or an app with limited functionality, there is no point to testing automation. Framework development and setup will equal if not exceed the time and effort required for manual testing. Moreover, the latter offers better flexibility when it comes to some minor changes in design or functionality.

A product that emphasises UI and UX will only benefit from subjective validation provided by manual testing: No automation tool can tell you if you need to use a bigger font or change the colors for better usability.

The following types of testing are best handled by hand:

• Exploratory Testing: Relying on a set of human skills, such as knowledge, experience, and creativity, this approach will benefit from manual execution. It typically has limited execution time and no comprehensive documentation to follow. Therefore, testing by hand proves to be valuable in this case.
• Usability Testing: The approach aims at validating such qualities of the product as usability, efficiency, and convenience for end-users. Manual testing helps you assess these qualities of the software, using human observation and testers’ first-hand experience.
• Ad-hoc Testing: A spontaneous, on-the-spot approach, it lacks any planning or preparation. That is why this testing method cannot be automated.

Test automation– ongoing projects, requiring frequent updates, and high performance

"When testing requires a methodical and repeated execution, that is better offered by machine than human.”

Kevlin Henney, an author, independent

software development consultant and trainer (Source)

Large projects typically benefit more from test automation. For example, it would be impossible to test such product as Google, which has over 2 billion lines of code, manually. Taking into account new products, features, and changes which might affect other parts of the system introduced by the company, using only a manual testing process becomes even more improbable.

In the environment where you need to rerun tests frequently, QA automation can be a reasonable investment. Often used as part of a continuous integration process as well as an agile software development approach, test automation allows you to test the whole product at every iteration with minimum effort and quick time to market.

Enterprise systems, which tend to put emphasis on data processing and performance instead of UI/UX, also can benefit greatly from test automation.

However, the trend continues to gain wider adoption: 86 percent of companies surveyed by PractiTest & Tea Time with Testers currently apply automation in their testing processes.

Automation is best applied to the following types of testing:

• Regression Testing: If your code base changes frequently and you introduce minor changes often, your regression testing can only benefit from automation. Not only does this approach allow for repeatability, it also saves your time and effort with multiple test scenario reruns.
• Load and Performance Testing: Using test automation tools, even one QA engineer can easily simulate thousands of concurrent users, database queries, and server requests to test how your system performs under load. Plus, you can track and measure various metrics in the process–a task that can never be processed by hand.

Finding a happy medium

There is no right way to answer the manual-vs-automated testing question. Neither of the approaches is better than the other. The truth is, having multiple benefits as well as drawbacks, each of them is best used under certain circumstances.

However, in most cases only a combination of both can give you excellent results. Working on a complex, feature-rich system, you might put performance first. Yet, you shouldn’t ignore product usability. Similarly, even a small product can benefit from automated load testing. Therefore, only a solid QA automation process, augmented by thorough manual testing, can deliver the results you need.

Additionally, you should take into account such aspects as timeframe, budget, and your team’s skillset, when considering manual vs automated testing approaches. If you are looking to hire a QA team, choose the one that can do both. Thus, you will be able to reap the benefits of both methods.

To learn more about Testing in Software Engineering, read our recent whitepaper Quality Assurance, Quality Control and Testing - the Basics of Software Quality Management.