Unit Testing
- Definition: Testing individual components or units of code to ensure they work as intended.
- Purpose: To verify that each unit of the software performs as designed.
- Scope: Narrow, focused on individual functions, methods, or classes.
- Who Performs It: Typically done by developers during the development phase.
- Tools: Jasmine/Karma, Jest, etc
Integration Testing
- Definition: Testing combined parts of an application to ensure they work together correctly.
- Purpose: To detect issues in the interaction between integrated units/modules.
- Scope: Wider than unit testing, focusing on the integration of different units/modules.
- Who Performs It: Often done by developers and sometimes testers after unit testing.
- Tools: JUnit (for Java integration tests), TestNG, Selenium (for web integration tests), etc.
System Testing
- Definition: Testing the complete and fully integrated software product to evaluate the system’s compliance with its specified requirements.
- Purpose: To validate the end-to-end system specifications.
- Scope: Broad, encompassing the entire application.
- Who Performs It: Performed by a separate testing team, often known as QA (Quality Assurance) team.
- Tools: Selenium, QTP, LoadRunner, etc.
User Acceptance Testing (UAT)
- Definition: The final phase of the testing process, where actual software users test the software to ensure it can handle required tasks in real-world scenarios, according to specifications.
- Purpose: To ensure the software meets the needs and requirements of the end users.
- Scope: Focused on user requirements and real-world usage.
- Who Performs It: Conducted by the end users or clients.
- Tools: UAT can be manual, but tools like HP ALM, Jira, and Trello can help manage the process.
These four types of testing are crucial in ensuring software quality and reliability before deployment to production environments.