When it comes to software testing, verification and validation are the two common terms you come across. Verification and Validation, often abbreviated as V&V, is the process in software testing to ensure that a particular software system meets the specified requirements and behaves as intended.
Verification and validation are often used together but are two individual processes in software testing. There are two aspects of V&V, as given below:
- A software product conforms to requirements (Producer view of quality).
- A software product is fit for use. (Customer view of quality).
This article will enlighten you on what exactly verification and validation in software testing are. Also, it will help you understand the major differences between verification and validation.
Verification and Validation in Software Testing
Verification and Validation (V&V) is an indispensable part of software testing. It ensures that the software product under development functions as expected and complies with the requirements of the end-users.
Sometimes, we also refer to V&V as software quality control . It is the responsibility of the quality assurance team and software testers to carry out the V&V process.
Many people get confused between verification and validation and end up considering that both the terms are the same. However, it is not true.
Barry W. Boehm, an American Software Engineer, succinctly described the difference between verification and validation as:
Verification: “Are we building the product right?”
Validation: “Are we building the right product?”
Building the product right implies that all the requirements or specifications are implemented correctly. On the other hand, building the right product refers to meeting the end user's requirements.
Therefore, from the above two definitions, we can say that there is a minor difference between verification and validation, and they are not the same.
What is Verification?
Verification is the process to verify that a software product meets the requirements and design specifications specified at the onset of the development process. We can refer to verification as static testing .
In other words, it is the process of checking whether the software product is achieving its goal without any defects or bugs. Moreover, it checks whether the development team is on the right track in developing the final product.
The primary purpose of verification in software testing is to check the design, database, and architecture of the software product. The quality assurance team generally carries out four different activities in verification, as follows:
- Inspection
- Reviews
- Walk-throughs
- Desk-checking
Testers carry out verification in every phase of the software development life cycle . Basically, they verify whether the output of a particular stage meets its input specifications.
What is Validation?
Validation is the process of verifying or checking the final product to ensure that it meets the actual requirements of the customers. It makes sure that the product is fit for use and conforms to the requirements of all the stakeholders, such as users, sponsors, investors, managers, etc.
We can refer to validation as dynamic testing. Like verification, testers perform validation in every phase of the software development life cycle. Moreover, validation involves various activities, such as unit testing, integration testing, system testing, and acceptance testing.
There are two types of validation, namely external validation, and internal validation. The internal validation implies that the development team understands all the requirements of the stakeholders and implements them correctly. If the software product meets those requirements, the software product is internally validated. Furthermore, internal validation makes use of unit testing, integration testing, and system testing.
On the other hand, external validation takes place when the stakeholders agree to accept the software product and express that it meets their needs. Such validation requires the use of acceptance testing.
In a nutshell, we can say that the aim of the validation is to physically ensure that the system behaves as expected by executing system functions through a series of tests.
Note: It is important to note that software testers carry out verification first and then validation, i.e., validation follows verification.
Examples of Verification and Validation in Software Testing
To understand what exactly verification and validation are, we shall take two simple and easy examples.
Example 1
Imagine you go to a restaurant and order blueberry pancakes. When the waiter brings your order out, how will you tell that the food you ordered is as expected?
Firstly, you will surely observe its appearance. You will notice the following things:
- Whether the food looks like pancakes?
- Are there blueberries in the dish?
- Do pancakes smell as usual?
Later, you taste the food to check whether it actually tastes as expected.
Therefore, verification is when you inspect the food with its visual appearance, while validation is when you verify the food by actually having it.
Example 2
Let us now consider a button named ‘Submet’. We need to check whether this button works correctly and carries out a specific task.
The verification process verifies the design document and corrects the spelling of ‘Submet’ to ‘Submit’. On the flip side, validation ensures that the button, Submit, is clickable and carries out its specific task.
Verification vs Validation - A Detailed Comparison
The following table draws a detailed comparison between verification and validation in software testing:
|
Verification |
Validation |
|
Verification checks whether the software product meets the specified requirements and design specifications. |
Validation ensures that the final software product meets the needs of all the stakeholders. |
|
In the verification process, we check whether we are developing the software product right or not. |
In the validation process, we check whether we are developing the right software product. |
|
It does not involve code execution. |
It always involves code execution. |
|
The quality assurance team is responsible for performing verification. |
Software testers are responsible for carrying out validation. |
|
Verification involves various activities, including inspection, reviews, walkthroughs, and desk-checking. |
Validation involves unit testing , integration testing, system testing, and user acceptance testing. |
|
It finds bugs at the early stages of development. |
It detects bugs that the verification process cannot. |
|
Verification comes before validation. |
Validation comes after verification. |
|
It is also referred to as static testing. |
It is also referred to as dynamic testing. |
|
The verification process targets the software product’s architecture and design specifications. |
The validation process targets the final product. |
|
Verification involves quality assurance. |
Validation involves quality control. |
When to Use Verification and Validation in Software Testing?
Since verification and validation are two different processes with different goals, software testers perform them in every phase of the software development life cycle. However, they perform verification first and then validation. Both processes play a vital role in the quality management of a software product.
The verification process aims to check the architecture, design, and database of the software product while validation intends to verify the actual software product.
Many times, the verification process cannot detect certain bugs. In such a scenario, the validation process detects those bugs.
Conclusion
Here we conclude our discussion on verification and validation in software testing. The testing team carries out both verification and validation (V&V), in every phase of the software development life cycle (SDLC).
The V&V process ensures that the software product meets the specified requirements and functions as expected. Moreover, verification focuses on developing the software product in the right way while validation focuses on developing the right product.
We hope this article has helped you understand the differences between verification and validation. Also, feel free to share your queries regarding this topic in the comments section below.
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