Difference between system, Integration and E2E test

System Test: 

• Tests the complete system as a whole to ensure it meets the specified requirements.
• Focuses on the entire application, including both functional and non-functional aspects.

Integration Test: 

• Tests the interactions between integrated units/modules.
• Verifies that combined modules or services work together as expected.

End-to-End (E2E) Test: 

• Tests the entire application workflow from start to finish.
• Ensures that the system works as expected in a real-world scenario, covering user interactions, backend processing, and integrations with external systems.

Comparison Summary

Feature	System Testing	Integration Testing	End-to-End (E2E) Testing
Scope	Entire system	Interaction between modules/services	Complete application workflow
Focus	Compliance with requirements	Module interactions	Real-world user scenarios
Stage	After integration testing	After unit testing	After system testing
Environment	Production-like environment	Integrated modules/services	Production-like environment
Tools	Selenium, QTP, TestComplete	Postman, JUnit, REST Assured, SoapUI	Cypress, TestCafe, Selenium
Examples	Full Jira app workflow	Jira UI and back-end API interaction	User creating and managing an issue in Jira