Manual vs. Automated QA Testing: Understanding the Key Differences

The creation of complex software systems is always prone to errors, and some errors can be critical. These errors can occur at any phase of the development lifecycle and can pose time and resource challenges for development teams. Therefore, it is important to detect and correct them as early as possible.

One way to detect these errors is by performing software testing at various stages of development, but these tests can be expensive, representing up to 50% of the total cost of software development. However, it is vital to perform them. In general, there are two types of software testing: manual and automated, and within them, non functional testing and functional testing.

Most organizations seek a solution that provides maximum results with minimal support. Both options have their advantages and disadvantages, but let's start at the beginning: what are manual or automated tests?

Manual Testing

Manual testing, as the name suggests, involves a tester manually validating some aspect of a piece of software, such as its functionality, performance, and user interface design.

In manual testing, the tester inputs data and evaluates its response to verify that it works correctly and meets the requirements. The implementation of test cases is one of the most important aspects of manual testing. These test cases are precisely constructed following predetermined testing strategies, user experiences, or specific criteria.

Automated Testing

The goal of automated software testing is twofold: to detect errors and validate performance. Automated tests make use of dedicated software capabilities to develop scripts. These scripts follow instructions that mimic the steps a user or other software would take with the software under test.

These scripts look for inconsistencies, and if differences are discovered, they are reported immediately. This technique allows the project team to identify issues quickly. It helps reduce the possibility of bugs spreading through the software and also allows teams to receive immediate feedback on the project and make constant changes.

In summary, during manual testing, a quality control engineer or tester manually carries out every test case without using scripts. Whereas in automated testing, a tester uses scripts and tools to execute all software testing cases.

And here comes the second point: within automated testing, there are functional and non-functional testing. Essentially, the fundamental difference is that the former evaluates whether what has been developed works, and the latter evaluates how what we are testing works.

What are Functional Tests? 

Functional testing is a type of testing that verifies that each function of the system operates according to the requirements specification. These tests are performed at all levels of testing, and software testing tools such as black-box techniques are often used for their design.

Each functionality of the system is tested by providing appropriate input, verifying the output, and comparing the actual results with the expected results. This testing involves verifying the user interface, APIs, databases, cybersecurity, client/server applications, and the functionality of the application under test.

What is Non-Functional Testing? 

Non-functional testing is a type of testing that seeks to check non-functional aspects (performance, usability, reliability, etc.) of a software application. It is explicitly designed to test the readiness of a system according to non-functional parameters that are never addressed by functional testing. In simple terms, non-functional testing affects customer satisfaction.

To understand it more simply, non-functional testing evaluates the characteristics of the developed system. It typically answers questions like: Is it easy to use? Does it operate at the appropriate speed? Are the data exchanged or stored protected? That is, it checks how the product behaves.

Types of Functional Tests

Functional tests are concerned with verifying if the software works correctly and meets user expectations. Here are some of the main types of functional tests:

• Unit Tests: Development teams use unit tests to determine if individual components or units of the software meet the functionality requirements. Performing unit tests ensures that the smallest functional parts of the software work correctly.

• Smoke Tests: Developers perform smoke tests after each new build to ensure stability and test critical functionality. Smoke tests verify the stability of the entire system, such as the functionality of the login page.

• Sanity Tests: Testers usually perform sanity tests after smoke tests. Sanity tests ensure that new specific features of the build or bug fixes in the application or software system work as they should. If smoke tests inspired bug fixes, sanity tests are the ones that determine if those bug fixes work.

• Regression Tests: Regression tests are used to ensure that any new code, update, or bug fix does not break the existing functionality of the application or software nor cause any instability in independent features.

• Integration Tests: Integration tests ensure that the individual modules of the software or application are connected and work together. They involve examining the logic and rendered values and ensuring that the modules integrate well with third-party tools while highlighting defects in exception handling.

• Beta/Usability Tests: Beta/usability tests allow real customers to test to ensure that a new product update works correctly before it is rolled out to everyone. Customers provide feedback on how well the update works, and developers may consider making further code changes for usability reasons.

Types of Non-Functional Tests

After determining if the software does what it should, non-functional tests can measure its performance under various circumstances. Here are the most common ones:

• Performance Tests: Performance tests allow developers to discover how the components of the software perform. It measures the overall quality of the software to determine its speed and scalability, such as measuring response times.

• Load Tests: Load tests help developers understand how a system operates under expected loads and user peaks.

• Load tests: help ensure that the software works and meets user expectations under normal loads, rather than testing it at extreme capacities.

• Stress Tests: Stress tests reveal how the software system performs under the most intense load conditions. For example, it can check how the system operates when more clients than usual are connected.

Difference Between Functional and Non-Functional Testing

It is clear that each type of test addresses different stages of the software evaluation process. In general terms, these are the main differences:

• Functional tests verify each function/feature of the software, while non-functional tests verify non-functional aspects like performance, usability, reliability, etc.

• Functional tests can be performed manually, while non-functional tests are difficult to perform manually.

• Functional tests are based on customer requirements, while non-functional tests are based on customer expectations.

• Functional tests aim to validate the actions of the software, while non-functional tests aim to validate the performance of the software.

• Functional tests are performed before non-functional tests.

Both functional and non-functional tests are necessary to have a quality product, but it is important to know and differentiate each one of them. If we know how to do it, we can structure and define more ambitious test plans, with more comprehensive coverage and ensure quality in areas that may not have been considered in previous instances.