June 25, 2023

The Power of Functional Testing. Benefits & Best Practices

Aleksandr Khomovych

QA Lead

12 min

In today’s digital era, software applications and systems play are crucial for every aspect of our lives and ensuring their reliability and functionality has become paramount. With the ever-increasing complexity of software and the diverse platforms on which it operates, the need for robust testing methodologies has grown exponentially. Among these methodologies, functional testing has emerged as a cornerstone in quality assurance, enabling companies to deliver software products that meet customer expectations while maintaining a competitive edge in the market.

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Functional testing is a software testing type that verifies whether a software application performs its intended functions correctly. By simulating real-world scenarios, this type of testing ensures that the application operates seamlessly and delivers the desired user experience. This type of testing plays a vital role in mitigating risks, detecting defects, and enhancing the overall quality of the software product.

Functional testing is crucial for validating the functionality and behavior of software applications as it helps identify defects early in the development cycle, reducing the cost of fixing issues and ensuring the delivery of a reliable and error-free software product. Brocoders is a leading software development company offering an array of services to meet various business needs. We provide comprehensive QA services to deliver the highest-quality web and mobile products. Continue reading to discover more information about functional testing and how our expertise can help you optimize the advantages of this testing approach.

What is Functional Testing?

Functional testing is designed to test modules in integration with the rest of the application, from the perspective of a user interacting with the user interface. In many cases, functional tests are written or expanded by quality engineers, although every software engineer should be aware of how these tests are written for the project and which of them are required to complete the particular feature set.

To get an adequate regression safety system for continuous delivery, you need both functional and unit tests as functional tests ensure comprehensive coverage of test cases based on user requirements and unit tests provide code coverage depth. This combined approach of functional and unit testing enhances the overall test coverage, detects defects at different levels of the software stack, and helps prevent regression issues, thus enabling a more robust and efficient continuous delivery process.

Software Testing Market Share by Service

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Source: https://www.technavio.com/

Functional testing can check various aspects of a software application, including:

  • Input and output. Functional testing can validate that a login form accepts valid credentials and denies access to invalid ones.
  • Functionality. It ensures that each function or feature of the software operates as intended. For instance, functional testing can verify that a shopping cart feature adds items, calculates the total cost accurately, and processes payments correctly.
  • User interface. The testing evaluates the user interface for usability and consistency. It checks that elements such as buttons, links, menus, and forms are functional and responsive and that the app provides a smooth and intuitive user experience.
  • Integration. It tests the integration between different components or modules of the software. It includes verifying that data is correctly shared between different app parts and that components interact seamlessly.
  • Database and data integrity. Functional testing can validate that the app interacts correctly with the database, storing and retrieving data accurately. It checks data integrity, ensuring that information is saved and displayed correctly.
  • Error handling. The testing examines how the app handles various error scenarios. It ensures that appropriate error messages are displayed and the app correctly recovers from errors without crashing or losing data.
  • Performance. Functional testing can also include evaluating the performance of specific functions or features to ensure they meet acceptable response times and scalability requirements.

These are just some examples of what functional testing can check. The specific areas and functionalities tested typically depend on the software application's requirements and scope.

Functional Testing Benefits

Functional tests are written from the user’s perspective and focus on system behavior that users are interested in. This type of testing is essential for many cases of software development as it brings the following benefits:

  • Meeting requirements. Functional testing ensures the software application or system meets the specified functional requirements.
  • Bug detection. By executing test scenarios, functional testing uncovers issues related to data processing, user interactions, calculations, and others. Detecting and addressing these bugs early in the development cycle can save time and costs in the long run.
  • User satisfaction. This testing type verifies that the software functions correctly from the end-user's perspective. It ensures a positive user experience, meeting user expectations and increasing satisfaction.
  • Improved software quality. By thoroughly testing the application's functionality, functional testing contributes to enhancing the overall quality of the software. Identifying deviations from expected behavior enables developers to fix issues and deliver a more reliable and robust product to end users.
  • Regression testing. Functional testing plays a significant role in regression testing, ensuring existing functionalities remain intact after changes. It maintains system stability and reliability.
  • Compliance and standards. The testing ensures that the software complies with industry standards and regulations. It verifies adherence to intended functionality, which is essential in sectors like finance and healthcare.
  • Reliability and stability. Functional testing identifies and eliminates defects that could cause failures or data corruption, enhancing performance and improving overall software reliability and stability.
  • Maintenance and support. This type of testing provides a foundation for maintenance and support. It aids in issue identification, troubleshooting, and creating a comprehensive test suite for future testing.

Considering all its benefits, functional testing is vital for ensuring software applications' quality, reliability, and user satisfaction across various cases.

Functional Testing Types

Functional testing can be performed using two approaches: automatic functional testing and manual functional testing.

Automatic functional testing involves using specialized tools and scripts to execute test cases and verify the functionality of the software application. It relies on automation frameworks and scripting languages to automate repetitive tasks and simulate user interactions. Among the benefits of automatic functional testing are:

  • Increased test coverage;
  • Faster test execution;
  • Ability to run tests repeatedly.

At the same time, manual functional testing is a hands-on approach where human testers manually execute test cases, interact with the software application, and validate its functionality. It involves real-time observation, exploration, and subjective evaluation. Manual testing is particularly beneficial for validating user experience, usability, and aspects that require human intuition and judgment. This type can be more cost-effective as it doesn’t require extensive automation infrastructure or scripting efforts.

Automated and manual functional testing can be divided into other types based on various factors. Here are some common types of functional testing:

User Acceptance Testing

User acceptance testing is a kind of black-box testing where two or more end-users are involved. It involves testing a software application in a real-world environment to ensure it meets the requirements and is ready for production use.

Unit Testing

Unit testing is done in the development phase of an application. It tests individual components or modules of the software application in isolation to ensure they function correctly.

Integration Testing

This type of functional testing verifies the interaction between different modules, components, or systems to ensure they work together seamlessly.

Smoke Testing

Smoke testing performs basic functionality tests to check if the critical functions of the software application are working correctly before proceeding with comprehensive testing.

System Testing

System testing evaluates the behavior and functionality of an integrated system as a whole. It ensures that all components and modules of the software application work together seamlessly and meet the specified requirements.

Security Testing

This type of testing checks for vulnerabilities and weaknesses in the software app to ensure that sensitive data is protected and the application is secure from unauthorized access.

Functional Testing Tools

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Functional Testing ToolDescriptionBest Use Cases
SeleniumAn open-source tool for web app testing across multiple browsers and platformsWeb app testing across multiple browsers and platforms
JUnitUnit testing framework for Java apps that allows for writing and executing tests to ensure the correctness and reliability of individual components or unitsTesting individual units or components of Java apps
CucumberAn open-source testing tool following the behavior-driven development (BDD) approach, facilitating collaboration and enabling the creation of executable specifications in a readable formatCollaboration between developers and non-technical stakeholders, enabling executable specifications
SoapUITool designed for testing SOAP and RESTful web services, ensuring their functional behavior and reliabilityTesting SOAP and RESTful web services
JMeterAn open-source tool for performance and load testing, enabling the assessment of web app performance, scalability, and stability under heavy loads and stress conditionsAssessing the performance and scalability of web applications
CypressJS-based end-to-end testing framework for modern web apps, providing comprehensive tools and features for efficient testing using JavaScript, including DOM manipulation and network stubbingEnd-to-end testing of modern web applications using JavaScript
PostmanTool for testing and validating RESTful APIs, providing a user-friendly interface, automated testing capabilities, and the API documentation generationTesting RESTful APIs and generating API documentation
TestCompleteA comprehensive functional testing tool supporting GUI testing, keyword-driven testing, and various scripting languages for testing desktop, web, and mobile appsComprehensive functional testing of desktop, web, and mobile apps
AppiumAn open-source tool specifically designed for automating mobile app testing on Android and iOS devices, supporting cross-platform testingMobile app testing on Android and iOS devices

The Process of Functional Testing. Typical Steps

A functional testing plan usually follows the following step-by-step process:

Test Planning


  • Determining the scope, objectives, and test strategy for functional testing.
  • Identifying the features or functionalities to be tested and establishing test priorities.

Test Case Design


  • Creation of test cases that cover various scenarios and functional requirements.
  • Specifying the inputs, expected outputs, and test data for each test case.

Test Environment Setup


  • Set up the necessary test environment, including hardware, software, databases, and network configurations.
  • Ensuring that the environment mirrors the production or target environment as closely as possible.

Test Execution

Stages: Executing the test cases based on the test plan and design. It involves running the tests, interacting with the software application, and comparing the actual and expected results.

Defect Reporting


  • Recording any defects or issues encountered during test execution.
  • Documenting the steps to reproduce the issue, along with relevant logs, screenshots, or supporting evidence.
  • Assigning appropriate priorities and severities to reported defects.

Defect Management

Stages: Tracking and managing reported defects throughout the testing process. Assigning ownership, monitoring the status, and facilitating communication between testers, developers, and other stakeholders. Retesting fixed defects to ensure they have been resolved.

Test Reporting


  • Generation of the test reports summarizing the test results, including the number of test cases executed, passed, and failed.
  • Providing metrics, insights, and analysis of the testing effort.
  • Communicating the findings to relevant stakeholders.

Test Closure


  • Evaluating the overall test coverage, completion, and exit criteria to determine if the functional testing process is complete.
  • Conducting a review and lessons learned session to identify areas for improvement and gather feedback for future testing efforts.

The steps of functional testing and their sequence may vary depending on the project, organization, and testing methodology employed.

Best Functional Testing Practices

Some best practices for functional testing include:

  • Comprehensive test planning. Define scope, objectives, and prioritize features based on their criticality.
  • Clear test requirements. Ensure well-defined and unambiguous functional requirements. It helps design accurate test cases and ensures proper alignment between the tests and the expected outcomes.
  • Design diverse test cases. Cover different scenarios and focus on positive/negative cases. Use techniques such as equivalence partitioning and boundary value analysis to maximize test coverage.
  • Effective test data management. Use a systematic approach to manage test data. Create relevant and realistic test data representing different scenarios, input combinations, and boundary conditions.
  • Mirror the production environment. Set up a test environment that closely resembles the target environment. Ensure that the hardware, software, and configurations are in place to replicate real-world scenarios accurately.
  • Utilize test automation. Automate repetitive and time-consuming tests for efficiency.
  • Systematic execution and reporting. Execute tests systematically and document results, including passed and failed tests, along with detailed information on encountered defects.
  • Robust defect management. Track, prioritize, and resolve defects promptly. Maintain effective communication channels between testers, developers, and other stakeholders.
  • Continuous improvement. Collect feedback, conduct test reviews, and identify areas for optimization. Embrace new technologies, methodologies, and industry best practices to enhance the overall effectiveness of functional testing.

Integrating these practices into your functional testing process can help you significantly improve the quality and reliability of software applications while optimizing testing efforts. Quality Assurance in Brocoders Brocoders is a reputable software development company offering a comprehensive suite of services to support clients in their software development and digital transformation journeys.

In addition to our top-notch QA services, we offer:

  • Custom software development;
  • UI/UX design;
  • Mobile app development;
  • Web development;
  • Dedicated development teams;
  • Technology consulting.

With a strong focus on delivering high-quality solutions, Brocoders has earned clients’ trust across diverse industries, including e-commerce, fintech, healthcare, and more. Our excellent rating on Clutch, a leading B2B ratings and reviews platform, showcases Brocoders' commitment to client satisfaction and our ability to meet and exceed expectations consistently.

We offer our clients functional testing services as part of our QA solutions. Brocoders' skilled QA team specializes in conducting thorough functional testing to validate software applications' functionality, reliability, and performance. By meticulously testing each aspect of the software against functional requirements, they identify defects and ensure it performs flawlessly.

We care about product quality and do our best to release bugless, smooth and seamless applications to the market. Our QA team utilizes best practices to deliver fast and secure software solutions. We use:

  • Product analysis and Test plan;
  • Unit tests. Each software component is safe to modify because of test coverage.
  • End-to-end automated tests. Automated use case scenarios protect releases from possible regressions.
  • Load/stress testing allows us to check how the app survives under significant loads.
  • Functional testing. Each newly developed feature is covered with test documentation
  • and tested progressively.
  • User acceptance testing (UAT). Part of our process is to get early feedback from the customer's team.
  • Regression testing cycles. We thoroughly test each build to protect it from
  • possible regressions.
  • Test management system (TMS). We use TMS for Jira for test cases, test planning
  • and test cycle execution tracking.
  • Bug tracking and health-check services. Services like sentry.io, NewRelic, and logz.io allow us to catch the bugs before users report them.

If you don’t have time to test the release or urgently need QA specialists to test new functionality, please contact us and get in touch with our QA team. We provide targeted and effective QA solutions, ensuring our clients receive holistic and reliable testing solutions that enhance the quality and performance of their software applications.

Wrapping Up

Functional testing is vital in ensuring software applications' quality, reliability, and user satisfaction. By thoroughly testing the functional requirements, organizations can identify and fix issues before deployment, saving time and resources while enhancing the user experience.

As software applications become more complex and user expectations rise, functional testing will likely remain critical in the QA landscape. Embracing emerging technologies, staying adaptable to changing methodologies, and focusing on delivering high-quality software will be key for organizations to thrive in the evolving QA landscape. With the help of professional QA services, companies can ensure the quality, reliability, and performance of their software applications, thereby maximizing customer satisfaction and achieving business success in an increasingly competitive market.

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