In software development, testing plays a crucial role in ensuring the quality and reliability of a software product. There are several types of testing that serve different purposes throughout the development lifecycle.

Unit Testing: This type of testing focuses on individual units or components of the software. It involves testing each unit in isolation to ensure its functionality, correctness, and reliability. Unit tests are typically written by developers and are executed frequently during development.

Integration Testing: Integration testing is conducted to verify the interaction and compatibility between different units or modules. It tests the integration points and ensures that they work harmoniously as expected. Integration tests are essential for detecting issues that may arise due to the interaction of various modules.

System Testing: System testing is conducted on the entire system or software application to evaluate its compliance with specified requirements. It covers end-to-end functionality testing, including user interfaces, database interactions, and external integrations. System tests are performed to validate the overall behavior and performance of the software.

By employing these different types of testing, software developers can identify and address issues at various levels of the application. Each type has its own focus and purpose, contributing to the overall quality assurance process.