Why Automate Functional Testing?

Uncover the compelling reasons why automating functional testing is not just a trend but a necessity for modern software development.

Why Automate Functional Testing?

We all acknowledge the role functional testing plays in ensuring that software performs its intended tasks accurately. However, a central question consistently resurfaces in strategy discussions, informal team conversations, and during the grind of testing cycles: Why should we automate functional testing?

This article delves into this pertinent issue, with a focus on providing insights that are valuable to QA teams, as well as to development teams at large.

The Dawn of Automation

Let’s start with a story. Imagine a testing team burdened with repetitive manual tests. A team member spends hours running the same test cases for various input scenarios and combing through the test results.

While it might seem like a thorough approach, the team soon realizes that it’s not sustainable. Human error creeps in; test cases fail, not because of issues with the software application but because the person executing the tests is fatigued. They turn to automated functional testing as a solution.

Discover our software testing case studies that show how we’ve helped top brands achieve their business and development goals.

What is Test Automation?

If you take the traditional definition of automation from industrial automation, you can say it refers to a technology that can automate manual processes, bringing about several other advantages:

  • Improvement in quality, as there are fewer human errors.
  • Improvement in production performance, given that more work can be achieved with the same amount of people, at a higher speed and larger scale.

This definition also applies perfectly to automated functional testing (or checking).

Test Design and Execution

Now, we would like to bring the “Zero Accumulation” theory forward. Basically, the features keep growing as time goes on (from one version to the next) but the tests do not grow. In fact, we haven’t heard of any company that hires more testers as it develops more functionalities.

Functional testing primarily focuses on the software’s behavior according to its requirements, while automated testing emphasizes the methodologies, tools, and scripts used to execute these tests automatically.

As a product grows, you have to choose what to test and what not to test, leaving many things untested.

The fact that the features grow with time means that the effort put into testing should grow in a proportionate manner. Here lies the problem of not having enough time to automate, given that there’s not even time for manual testing!

test automation excuse diagram

Ernesto Kiszkurno, an Argentine consultant at a firm specializing in quality and process engineering, says that the hardest thing (aka most expensive) in testing is design and execution. You would consider that the design is cumulative, given that you design and record it in spreadsheets or documents.

The difficulty is that test executions are not cumulative. Every time a new version of the system is released it’s necessary (well it’s desirable, yet should be necessary) to test all the accumulated functionalities, not just the ones from the last addition. This is because it’s possible that some of the functionalities implemented in previous versions change their desired behavior due to the new changes. 

The good news is that automation is cumulative. It’s the only way to make testing constant (without requiring more effort as time goes by and as the software to be tested grows). The challenge is to perform testing efficiently, in a way that pays off, where you can see results and in a way that it adds value. 

test effort vs product versions graph

When people say they’re doing automated functional testing, they’re using tools to automatically check that the software functions as expected. It’s a blend of both worlds – ensuring functionality while saving time and effort.

Learn the differences between functional and non-functional testing in this article.

What Automated Functional Testing Is Not

Automated functional testing is not a replacement for unit testing, integration testing, or user acceptance testing. These types of functional testing have their own places in the software development lifecycle. Automated testing tools can aid in smoke testing, regression testing, and performance testing. However, the focus of this article is on automating functional testing specifically, which can include various types of functional testing like boundary value analysis or equivalence partitioning.

Why Automate Functional Testing: The Core Reasons


One of the major benefits of automated functional testing lies in the efficiency it brings to the testing process. You can run tests overnight or over the weekend, so by Monday morning, you’ve got your test results ready for review. Automated tests can cover multiple test cases simultaneously, effectively reducing the test cycle time.


Manual tests introduce the variable of human error. By automating functional testing, you standardize the testing process. Each time a test case runs, it performs the exact same steps, reducing errors and increasing reliability.

Comprehensive Test Coverage

Automated functional tests also allow for more comprehensive test coverage. You can execute test cases across different browsers, platforms, and environments, something exceedingly difficult to achieve through manual testing alone.


The test scripts you create for functional tests can often be reused in other testing phases. This reuse of test scripts cuts down on test creation time and aids in continuous testing as your software evolves.

Faster Feedback

Quick feedback is crucial during development cycles. Automated tests can provide rapid feedback to developers, highlighting failed test cases immediately. This speeds up the development process and brings a product to market more quickly.


You can scale automated functional tests to any extent you require. Need to perform extensive testing on a new feature? Want to add more test cases to your test suite? Automated tests are up to the task.

Cost-Effectiveness Over Time

Automated functional testing may seem like an upfront investment, especially in automated testing tools and training. However, over the long term, test automation proves to be cost-effective. By decreasing the time spent on test maintenance and test execution, the testing teams can focus on creating more intricate and challenging test cases, adding value to the software development process.

Resource Optimization

In traditional manual testing, a significant chunk of resources is devoted to running repetitive test cases. With automation, team members can be redeployed to focus on more complex test cases that require human ingenuity, or even different types of testing like load testing or user acceptance testing.

Minimizing Human Error

We all know that human error is inevitable. Even the most diligent tester can miss something after running manual tests for hours on end. Automated functional testing eliminates this risk. The testing framework follows a set test script and provides consistent test results, free from human error.

Continuous Integration and Continuous Testing

With the advent of DevOps, continuous integration has become the norm. Automated functional testing fits seamlessly into this development process. Every time a piece of code is changed, tests can be run automatically, ensuring that new changes haven’t broken existing functionalities.

Enhancing the Quality of Software

At the end of the day, automated functional testing is all about enhancing the quality of the software application. By automating test cases, you improve test coverage, reduce the chances of human error, and receive quicker feedback, all of which contribute to a more robust, reliable software product.

Selecting the Right Tools and Strategy

Choosing the right automated functional testing tools is crucial. There’s a wide array of testing tools available in the market. These tools differ in capabilities — from simple record-and-play tools to those that require detailed test scripts in specialized programming languages.

It’s equally essential to develop an automated functional testing strategy. This involves deciding the extent of automation you need, planning the test data, and determining which test cases to automate. Often, test cases that are frequently executed, are too complex for manual testing, or that need to be run on multiple hardware configurations are excellent candidates for automation.

Best Practices for Automated Functional Testing

For those who have decided to embark on the journey of automated functional testing, knowing some best practices can go a long way.

Test Creation and Maintenance

One of the challenges in automated functional testing lies in test creation and test maintenance. Ensure that your test cases are modular and reusable. This allows for easier maintenance and adaptability as your software undergoes changes.

Don’t miss this episode of the Quality Sense Podcast from Test Automation at Scale, with Federico Toledo and Andy Knight.

Cross Browser Testing

Don’t underestimate the importance of cross-browser testing. Your web applications must perform consistently across all browsers and platforms. Automated functional testing tools often provide capabilities for cross-browser testing, ensuring that your user interface looks and functions as expected everywhere.

Test Data Management

Test data is crucial in executing test cases effectively. Whether you are running unit tests or integration tests, the right set of data can make a significant difference in your test results.

Data-Driven Testing

In data-driven testing, you can execute the same test case by feeding it multiple sets of data. This is especially useful in functional test automation where varying conditions and scenarios can be tested in a single test cycle.

Parallel Testing

You can run tests in parallel to speed up your test cycle. This allows multiple test cases or test suites to be executed simultaneously, which is beneficial in continuous testing environments.

API Testing and User Interface Tests

While functional tests often focus on the user interface, it’s essential not to overlook API testing. Ensuring the backend functionalities are working correctly is as important as confirming that the front-end elements are functional.

Integration with Development Processes

Automated functional testing should not be an isolated activity. Integrate it into your development process for maximum impact. Continuous integration tools can trigger a test suite to run whenever a new code commit happens, providing immediate feedback to the development team.

Our approach to service delivery includes greater transparency, ensuring that every stakeholder is informed and satisfied throughout the project’s lifecycle. Dive into how we make testing progress visible in this article. And learn more about how our testers can elevate your software quality in this just here.

The Future of Automated Functional Testing

The role of automated functional testing is growing. With the advent of machine learning and artificial intelligence, the testing tools themselves are becoming smarter. They can now understand human behaviors better and simulate a variety of complicated user scenarios. This is making automated functional tests more accurate and versatile.


Why automate functional testing? To sum it up, automated functional testing brings efficiency, consistency, and scalability to the testing process. It allows for extensive test coverage, minimizes human error, and offers quicker feedback loops during the development process. It also complements other testing methods, like unit testing and regression testing, rather than replacing them.

In a world that’s rapidly digitizing, ensuring the functional integrity of your software applications is not just recommended but essential. Automated functional testing is not a checkbox to be ticked off but a strategic approach to quality assurance.

By integrating automated functional testing into your development and testing processes, you set the stage for delivering software that is not just functional, but exceptional.

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