Every software project revolves around three key aspects: Quality, Cost, and Time. The goal is to deliver a high-quality product while managing costs and meeting deadlines effectively. For this reason, a software product must go through functional testing.

This guide will explore the fundamentals of functional testing and compare it with non-functional testing.

What Is Functional Testing?

Functional testing aims to confirm that the system's features operate correctly according to the defined requirements. These requirements can be gathered from users or provided by stakeholders, such as the development team or product owner.

For this reason, functional testing is often referred to as specification-based testing. The primary objective of functional testing is to confirm that the software delivers the expected outcomes without examining its internal code or implementation.

functional testing

How Functional Testing Works?

Functional testing starts with understanding the project’s requirements, often derived from user stories. It then involves converting these user stories into precise, actionable requirements, which are then used to create corresponding test cases.

A typical user story follows this structure:

As a [role]: Identifies the user or stakeholder who will benefit from the feature.

I want [feature]: Describes the specific functionality or feature the user needs.

So that [benefit]: Explains the reason behind the request, highlighting the feature's benefit or goal.

Once the user story is broken down, test cases are developed to verify that the feature works as intended and delivers the expected outcomes.

For instance, consider a user story like this:

"As a customer, I want to view my order history online to track the status of my purchases."

This provides a useful starting point but is insufficient for the development and QA teams. Testers need to collaborate with end users, understand their perspective, and refine the user story into a more specific context to confirm the feature meets the actual needs.

To turn this user story into actionable requirements, Tester breaks it down into manageable tasks. A broad user story like this can be divided into smaller, more specific components. For example, you might identify tasks such as designing the UI for order history, implementing the backend logic, and validating that orders are accurately displayed.

This approach helps mitigate risks and confirms that each feature part is developed and tested thoroughly. You can streamline development and testing processes by addressing these smaller chunks individually, making them more efficient and focused.

low code testing

Differences Between Functional and Non-Functional Testing

Functional and non-functional testing serve different purposes in software quality assessment. Here's a detailed comparison of these two testing types:

1) Purpose

Functional Testing focuses on verifying whether the software performs its intended functions. It confirms that each feature works according to the specified requirements.

It involves assessing how the software's components interact and verifying that the system delivers the expected outcomes when provided with specific inputs.

In contrast, non-functional testing types assesses usability, security, and performance characteristics. It focuses on how well the software handles different conditions and scenarios, such as assessing speed, stability, and ease of use.

2) Focus

Functional testing verifies whether the software meets its intended purposes and performs the specified tasks correctly. It targets specific features and functionalities to confirm that they work as expected.

Functional testing examines individual functions and interactions to identify any discrepancies between the actual behavior of the software and the expected outcomes. This thorough evaluation confirms that all parts of the application function correctly and the software meets user needs and business objectives.

On the other hand, Non-functional testing determines how well the software performs and behaves under various conditions, focusing on aspects like efficiency and user experience. This includes evaluating factors like system responsiveness and security measures.

3) Scope

Functional testing is more targeted, focusing on particular software features and functionalities. It initiates by verifying that each function operates as intended and aligns with business logic specifications. It also involves validating input data to confirm that it produces the expected outcomes and that test cases are executed correctly.

Functional testing involves comparing actual results with expected outcomes to ensure consistency and accuracy. It also considers non-ideal conditions and tests how the application performs under less-than-ideal scenarios.

Non-functional testing, however, covers a broader range of attributes and functionality. It includes assessing overall software quality, such as performance and user experience.

4) Test Criteria

In Functional testing, criteria are usually straightforward and based on expected functional outcomes. Test results are usually categorized as pass or fail, depending on whether the software meets the specified functional requirements.

Non-functional testing involves more complex criteria, often including benchmarks or thresholds, such as acceptable response times or security standards.

5) Objective Measurement

Functional testing often results in binary outcomes (pass/fail) based on whether the software behaves as expected. Test criteria and standards play an important role in this process. Key elements include expected outputs, acceptance criteria, defect severity, and the extent of test coverage.

Performance aspects such as response time and metrics are vital for assessing the system’s behavior under different conditions. Response time should be measured under normal load conditions, and performance metrics like CPU and memory usage are also important and should be observed as the system's load increases.

In contrast, Non-Functional testing involves quantitative measurements and benchmarks for various attributes, such as speed and security, providing a more detailed assessment of the software’s overall quality.

6) Frameworks and Technologies

vStellar Test, Selenium, JUnit, and TestNG are designed to test specific software functions. vStellar Test is a powerful test automation framework that simplifies the functional testing process. Its user-friendly interface and natural language processing (NLP) capabilities allow testers to create and execute test cases using plain English, eliminating the need for complex coding.

For Non-functional testing, tools such as JMeter, OWASP ZAP, and LoadRunner assess software performance, security, and various quality aspects.

Functional vs Non-Functional Requirements

Understanding the distinction between functional and non-functional requirements is crucial for developing software that meets user expectations and operational standards.

Functional Requirements

These define what the software should do. They describe specific behaviors, functions, and interactions that the software must support. For example, functional requirements might specify that a user can log in, search for products, or complete a purchase.

Non-Functional Requirements

These describe how the software performs its functions. They focus on attributes like performance, security, usability, and reliability. For instance, non-functional requirements might specify that the software should handle 1,000 users simultaneously, be secure against data breaches, or load within 2 seconds.

process of functional testing

2 Main Approaches of Functional Testing

Functional testing can be performed through two main approaches: Manual and Automated. Let’s explore both methods and determine which is more suitable for functional testing.

Manual Functional Testing

In the manual approach, QA testers manually design and execute test cases by directly interacting with the software to assess its functionality. This method provides hands-on validation but is often costly and time-consuming and may not catch every potential issue. It is less efficient for large-scale or complex applications.

Automated Functional Testing

The functional testing process is done in QA automation using specialized tools. These tools create and run automated test scripts, significantly reducing time, costs, and human effort. This approach offers greater efficiency and consistency, making it the preferred option for repetitive or extensive testing tasks.

For example, imagine you need to execute 200 test cases manually. This could take a team of testers several days, factoring in the complexity and resource allocation. However, with an automated tool, the same testing could be completed in just a few hours with less effort.

automated function testing

Get Your Functional Testing Done Faster With More Accuracy

Automating functional testing can significantly increase the efficiency and accuracy of the testing process. vStellar Test is an advanced test automation framework that perfectly automates functional tests for web, mobile, API, and desktop applications. It can easily create and execute test cases using a user-friendly interface and natural language processing (NLP) capabilities.

This eliminates the need for complex coding, allowing testers to focus on verifying functionality. Automating with vStellar Test can reduce manual effort, minimize testing time, and integrate with popular CI/CD tools, enabling continuous testing and faster delivery of high-quality software.

Ready to automate your testing process? Contact vStellar Test and experience a new level of software quality!

FAQs

What Is the Main Objective of Functional Testing?

The main objective of functional testing is to verify that the software functions according to the specified requirements and provides the expected outcomes for the end user.

How Does Functional Testing Differ From Regression Testing?

Functional testing focuses on verifying specific software functions, while regression testing confirms that new code changes do not negatively impact existing functions.

Can vStellar Test Be Integrated With CI/CD Pipelines?

Yes, vStellar Test integrates with popular CI/CD tools, allowing continuous functional testing throughout the development cycle for faster releases.

What Skills Are Needed to Automate Functional Testing With vStellar Test?

vStellar Test uses Natural Language Processing (NLP), which allows testers to write test cases in plain English, eliminating the need for advanced coding skills.

Can vStellar Test Handle Cross-Browser Testing?

Yes, vStellar Test supports cross-browser testing, allowing you to verify that your application functions correctly across different browsers and platforms.

Complete Guide on Functional Testing & Automation with vStellar Test

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