🚘Functional Testing

What is Functional Testing?

Functional testing refers to testing software to verify that it performs according to defined functional requirements and specifications. In simple terms, it tests the functionality or features of an application to ensure they work as intended.

Functional testing aims to answer two basic questions:

" Does the software do what it is supposed to do?"

" Does the software meet the business and user requirements defined for it?"

Functional test cases are designed based on the specified functional requirements of an application. The test cases are then executed to verify that the software performs as documented.

Example of Functional Testing

Let's say you have an e-commerce website with the following requirements:

• The checkout page should allow customers to enter their shipping address details.

• After entering an address, the system should calculate applicable taxes and display the total amount due.

• The system should allow customers to apply valid promotional codes and adjust the total as needed.

Test cases for these requirements could be

• Enter a valid shipping address and verify taxes are calculated correctly.

• Enter an invalid address and ensure an error message is displayed.

• Apply a valid promotional code and verify the total amount decreases by the specified amount.

• Apply an invalid code and ensure an error message is shown.

The objective of these test cases is to verify that the checkout functionality performs as specified in the requirements.

Importance of Functional Testing

Functional testing helps ensure that the developed software meets design specifications and performs as expected. It exposes defects early in the development lifecycle, reducing rework costs and helping produce higher quality software.

Good functional test cases should cover

• Normal flows - Test valid, expected inputs and functionality

• Edge cases - Test invalid inputs and boundary conditions

• Error handling - Verify exceptions and error messages

• Performance - Test performance under load

What are the advantages of Functional Testing?

• It produces a defect-free product.

• It ensures that the customer is satisfied.

• It ensures that all requirements met.

• It ensures the proper working of all the functionality of an application/software/product.

• It ensures that the software/ product work as expected.

• It ensures security and safety.

• It improves the quality of the product.

Example: Here, we are giving an example of banking software. In a bank when money transferred from bank A to bank B. And the bank B does not receive the correct amount, the fee is applied, or the money not converted into the correct currency, or incorrect transfer or bank A does not receive statement advice from bank B that the payment has received. These issues are critical and can be avoided by proper functional testing.

What are the disadvantages of Functional Testing?

• Functional testing can miss a critical and logical error in the system.

• This testing is not a guarantee of the software to go live.

• The possibility of conducting redundant testing is high in functional testing.