Functional Testing and Non-functional Testing

 

Feature	Functional Testing	Non-Functional Testing
Focus	Tests the functionality of the system	Tests aspects other than functionality, such as performance, usability, and security
Objective	Ensures that the system behaves as expected based on functional requirements	Evaluates system attributes like performance, reliability, and user experience
Type of Requirements Tested	Tests against functional requirements	Tests against non-functional requirements
Examples of Testing Types	Unit testing, integration testing, system testing, acceptance testing	Performance testing, usability testing, security testing, reliability testing
Test Cases	Written based on functional specifications	Derived from non-functional requirements and constraints
Test Scenarios	Cover typical user scenarios and use cases	Address scenarios related to performance, scalability, reliability, etc.
User Interface Testing	Part of functional testing to ensure the UI meets requirements	Non-functional aspects like usability may be tested separately
Automation Suitability	Often automated for repetitive tasks and regression testing	Automation may be used for certain non-functional tests, but manual testing is common
Scope of Testing	Generally broader as it encompasses all functional aspects of the system	Focused on specific attributes outlined in non-functional requirements
Performance Metrics	Measures how well the application functions in terms of features and user expectations	Measures aspects such as response time, throughput, and resource utilization
Test Execution Speed	May be slower due to the complexity of functional scenarios	Depends on the type of non-functional test; some may take longer to execute
Examples of Tools/Frameworks	Selenium, JUnit, TestNG	Apache JMeter, LoadRunner, JIRA for performance tracking
Error Identification	Focuses on identifying functional defects	Focuses on identifying issues related to performance, security, usability, etc.
Verification vs Validation	Emphasizes validation (are we building the right product?)	Emphasizes verification (are we building the product right?)
Validation Criteria	Based on functional requirements and specifications	Based on non-functional requirements, standards, and user expectations

In summary, functional testing ensures that a software application behaves as expected in terms of its features and functionalities, while non-functional testing assesses aspects beyond functionality, such as performance, usability, and security. Both types of testing are essential for delivering a high-quality and reliable software product.