Performance Testing vs Functional Testing

Testing is an important phase in the software development life cycle. It checks and validates all kinds of programs to determine malfunctions that could introduce trouble later or in the future such as processing issues, usability, and so on. These problems are very dangerous from a business point of view that profit by selling software. When a company loses its customer trust, it loses reputation, loyalty, revenue, and so on. Functional testing and performance testing are one of the two testing and QA that entitle developers and performance engineers to guarantee the quality of code.

Performance Testing

Performance testing is a type of software testing that ensures software applications perform as expected under load. It is a testing technique used to determine system performance in terms of sensitivity, reactivity, and stability under specific workload conditions.

Performance testing is a type of software testing that focuses on evaluating a system’s or application’s performance and scalability. Performance testing aims to identify bottlenecks, measure system performance under varying loads and conditions, and ensure that the system can handle the expected number of users or transactions.

Functional Testing

Functional testing is a type of testing that ensures that each function of a software application operates to the requirements and specifications. This testing is not concerned with the application’s source code. Each software application functionality is tested by providing appropriate test input, anticipating the output, and comparing the actual output to the expected output. This testing focuses on the Application Under Test’s user interface, APIs, database, security, client or server application, and functionality. Manual or automated functional testing is available.

Performance Testing vs Functional Testing

Difference between Performance testing and Functional testing:

Aspect	Functional Testing	Performance Testing
Purpose	Verifies that software functions as intended and meets specified requirements.	Evaluates the system’s performance under various conditions like load, stress, and scalability.
Focus	Tests individual functions or features to ensure correct behavior.	Measures responsiveness, speed, and stability of the entire system.
Scope	Includes unit testing, integration testing, system testing, etc.	Involves load testing, stress testing, scalability testing, etc.
Testing Criteria	Validates functionality, user interface, data handling, etc.	Assesses speed, reliability, scalability, and resource usage.
Examples	Unit testing, integration testing, system testing, acceptance testing, etc.	Load testing, stress testing, endurance testing, scalability testing, etc.
Key Metrics	Pass/fail based on functional requirements.	Response time, throughput, resource utilization, error rates, etc.
Users’ Perspective	Concerned with what the system does.	Concerned with how well the system performs under different conditions.
Tools	Selenium, JUnit, TestNG, etc.	Apache JMeter, LoadRunner, Gatling, etc.

Conclusion:

Performance testing ensures that application software can handle real-world scenarios and address any issues that may arise in order to deliver a robust and efficient product to end users. Functional testing, on the other hand, ensures that software is valid in terms of functional and business requirements.