What is Functional Testing in Software Testing

What is Functional Testing in Software Testing?

  • Functional testing is a process of checking the correctness and completeness of the functionality of the build.
  • Functional system testing is the process of checking internal functionality depending on external functionality.
  • This type deals with the functional requirements or specifications of an application to be tested by providing the input and comparing it with the expected output.

Types of Functional Testing

A few major types of Functional Testing in software testing are:

  1. Smoke Testing
  2. Sanity Testing
  3. Integration Testing
  4. System Testing
  5. Regression Testing
  6. User Acceptance Testing

What We Are Testing In Functional Testing?

We check functionality and the coverage are:

  1. Behavioral Coverage
  2. I/P Domain Coverage
  3. Error Handling Coverage
  4. Back End coverage
  5. Service Level Coverage
  6. Calculation base coverage

1. Behavioral Coverage

In this, we check the property and behavior of the object.


Property of check box – Do tick when the user clicks

The behavior of check box – Check/Uncheck

Property of Drop-down – to show hidden list on click

The behavior of drop-down – Show/hide list

2. I/P Domain Coverage

Here we check the input data with different conditions and can use Boundary value analysis and Equivalence class partitioning techniques.

3. Error handling coverage

Error handling coverage includes checking whether the system shows an error message or not as per the requirement.

If in customer requirement, the mobile number should accept the 10 digits, and the developer build according to if the customer enters 2 digits and click on the OK button then the system should highlight a text box with red color with the error message “Please enter 10-digit mobile number”

So, this is the process of validation.

4. Back-end coverage

The back end of any software system is the database.

In back end coverage developer checks whether the entered information from the user gets stored in the database or not

We also check whether data get fetched from the database or not.

Back-end coverage

5. Service Level Coverage

In SRS, BA creates a functional flow diagram and accordingly tester test the sequence of functions and modules.

This aspect of sequentially functional modules gets tested in service-level coverage.

6. Calculation base Coverage

Here arithmetic operations can be tested

Arithmetic operation means addition, multiplication, sub and division, etc

Example-If we add 1 thing in the cart and it is 900 rs then the total is 900 and again we add 2 things which are 50 rs then the total is 1000.

Then remove 1 thing of 50 rs than 950 in total. This gets checked in this coverage.

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