Verification vs. Validation in Software Testing

Software testing is a critical driver of a digital solution’s performance. Without it, a software product may fail to meet expectations. At present, there exist a dozen of software testing approaches that promise flawless outcomes. However, two types of testing that come at the top are Verification and Validation testing.

Those who work closely in the field of custom software development services may already know the terms we’re talking about. Verification and validation are two commonly followed software performance testing processes for determining whether a solution meets its expectations. Both are cardinally important for the success of the software development lifecycle.

In this blog, we’ll understand the meaning, significance, and other key fundamentals of verification vs. validation testing in custom software development. We’ll also explore scenarios where each methodology is an ideal fit and can make a lasting difference.

So, let’s dive right in.

What are Verification and Validation in Software Testing?

The software testing pyramid encompasses various methods and techniques used throughout the software development lifecycle to ensure quality, functionality, and performance.

These types include:

• Unit testing
• Integration testing
• System testing
• Acceptance testing
• Functional testing 
• Regression testing, among more.

This image showcases the Software Testing Life Cycle phases as followed by Unified Infotech.

Each type serves a distinct purpose, from verifying individual components to validating the entire system’s functionality. Verification and validation testing fall under the broader category of functional testing in software testing. However, they serve different purposes. 

Verification Testing involves gauging and improving the quality from the perspective of developers, whereas validation testing evaluates a software product or platform from the perspective of end users. In other words, verification testing ensures that a software solution is built in harmony with the design documents, standards, and specifications. On the other hand, validation testing involves running a software through real-world scenarios, ensuring it meets the requirements of the target audience.

Both of these software testing methods emphasize a thorough scrutiny of a solution’s behavior and properties when put in certain environments. Any potential defects or discrepancies, if found, are tackled immediately to make sure the end outcome is fully compliant and market-ready.

What is Verification Testing?

Exploring its role, significance, and methodology

Verification Testing, being an integral part of software functional testing, verifies whether a software product fulfills the objectives behind its creation and is devoid of defects or bugs. Verification involves end-to-end software testing, examining every predetermined software specification – the plan, code, design, and documents – to ensure the product meets them.

The process involves keeping tabs on vital activities, such as system properties, business requirements, code walkthrough, and design review. The overarching goal is to ensure unfailing quality in every aspect of the software solution, from architecture to design.

Benefits of Verification Testing

Verification testing paves the way for software development processes aligned with global market and industry standards. The key benefits of it are outlined below:

• Frequent verification reduces the number of bugs and defects that may appear in later stages.
• Verifying at each stage gives insights into potential improvements needed in future stages.
• Even if bugs can’t be fixed immediately, verification helps QAs predict emerging issues and prepare to handle them.
• Verification keeps the software closely aligned with customer and business requirements at every stage.
• This process reduces the need for unnecessary work as development progresses.

How is Verification Testing Performed?

Verification software testing lifecycle comprises four methods:

• Peer Reviews: It involves providing the software product to others and asking them to review it. They can share their views about the product’s quality and help identify flaws.
• Inspections: A particular team inspects the software product and helps find potential faults and critical sections.
• Walkthrough: It involves demonstrating the software to a group of people who are free to ask their doubts. This method can help find potential problems.
• Desk-Checking: It is the process of reviewing a software’s source code. The development team usually desk-checks a program to ensure the algorithms work fine.

When to Use Verification Testing?

The QA and testing team must conduct verification tests at every phase of the software development cycle. One must ensure that these evaluations are done before implementing any feature. Suppose there’s a button called “Add to Cart.” Before developing it, it’s wise to conduct a verification test to understand its predetermined requirements. The software development team can then work on every element and feature without missing guidelines.

Here are some common scenarios when verification testing comes in handy:

• Before User Acceptance Testing: Ensures the system meets all requirements and is error-free before user testing.
• Before Code Integration: Verifies individual modules to ensure they meet design specifications before integration.
• During System Integration: Checks that integrated system components meet defined requirements and function as expected.
• After Software Updates: Verifies that updates or patches are implemented correctly without introducing new issues.
• When Requirements Change: Ensures the system complies with updated or revised requirements.
• During Design Reviews: Confirms that the design aligns with initial requirements and documentation.

Now that you’re familiar with verification testing’s role and significance, let’s understand validation testing in a nutshell.

What is Validation Testing?

Exploring its role, significance, and methodology

Validation testing in software testing involves evaluating the product to ensure it performs as intended in real-world scenarios and meets user expectations. The process comprises smoke testing, functional testing, integration testing, and other viable techniques. 

Validation testing often occurs in the later stages of development and involves checking whether the product delivers the desired outcomes, ensuring it is both functional and user-friendly in the target environment.

Benefits of Validation Testing

If software doesn’t meet market needs, what good does it serve? Validation testing ensures that a software product or platform is ideal for the market it’s intended for. Some of its benefits include:

• Missed bugs during verification are often detected during validation testing.
• If specifications are incorrect, validation tests reveal their shortcomings.
• Time and effort spent fixing issues prevents a bad product from reaching the market.
• Validation tests ensure the product meets customer demands, preferences, and expectations under various conditions (e.g., slow connectivity, low battery).
• They also verify the software’s cross-browser compatibility across different browser-device-OS combinations.

How is Validation Testing Performed?

Validation software testing lifecycle involves the following 4 phases:

• Design Qualification: It involves designing a validation testing plan based on the client’s requirements.
• Installation Qualification: It involves following the validation testing plan and installing the software accordingly.
• Operational Qualification: It involves testing the software using unit testing, integration testing, and more.
• Performance Qualification: It involves verifying whether the software can work in the real world per the requirements.

When to Use Validation Testing?

The quality assurance team must validate the product after every step in its development process. Unit test, one of the widely used software testing methodologies and a subset of software validation, is conducted after developing every unit of code. 

The integration test, another part of the validation process, is run after different modules have been fully developed and are ready for integration. Another aspect called cross-browser testing involves assessing every feature works as needed on various browser-device-OS combinations. 

For instance, once the team has fully developed the “Add to Cart” button, check whether it performs perfectly on different devices and browsers. This is a simple explanation of validation testing.

Some common scenarios where validation testing is used include:

• After Major Changes or Enhancements: When updates or new features are added, validation testing ensures they align with stakeholder expectations and don’t negatively affect functionality.
• Before Product Launch: Conducted to verify that the product meets customer requirements and performs as expected in real-world conditions.
• During Beta Testing: Used in beta testing to gather feedback on whether the product meets user needs and expectations.
• After System Completion: Once the system is fully developed, validation testing ensures the final product meets stakeholder requirements.
• During User Acceptance Testing (UAT): Used to confirm the product meets end-user needs and works correctly in real-world scenarios.

Post-Implementation Review: After deployment, validation testing ensures the product continues to meet stakeholder needs and functions as intended.

Using Software Verification and Validation in Software Testing

Verification and validation software testing methodologies, as now apparent, are an indispensable part of a software development lifecycle. Both of these processes can help determine whether the software product’s the right industry and market fit. 

The image below sheds light on the verification and validation software testing tools and how these work in tandem toward a common goal and shared successes.

Let’s now understand the difference between verification and validation in software testing.

How Does Verification Testing Differ from Validation Testing?

Understanding the Key Differences

Final Thoughts

There must be an effective verification and validation plan, along with flawless implementation, to deliver the best final software to customers. Think of them as two crucial authentication layers that ensure the product is developed according to the plan and specifications.

Verification ensures that the software is built correctly, according to the defined requirements, while validation checks if the product actually meets the users’ needs and expectations. 

By properly applying verification and validation in software testing, you can identify and eliminate bugs that could negatively impact the user experience and lead to criticism from end-users. This thorough process helps ensure a smooth, functional product that meets both technical and user expectations.