Testing (Unit, Integration, E2E)

Testing is the process of evaluating software to ensure it functions correctly, reliably, and as intended. It includes different testing levels such as unit testing, integration testing, and end-to-end (E2E) testing.

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Unit Testing

Tests individual functions or components in isolation.
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Key traits:
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• Fast, automated, and gives immediate feedback
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• Uses mocks or stubs to remove dependencies
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• Tools: JUnit, pytest, NUnit
  

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Integration Testing

Verifies how multiple modules interact and exchange data.
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Key traits:
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• Ensures components work together as intended
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• Can be incremental or executed all at once
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• Tools: Postman, Selenium, JUnit Integration
  

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End-to-End (E2E) Testing

Validates full user workflows across the entire system.
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Key traits:
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• Covers UI, backend, and APIs
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• Ensures real-world reliability and user experience
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• Tools: Cypress, TestCafe, Selenium
  

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Simple Example

A login feature may go through:
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Related Terms

• Quality Assurance (QA)
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• A/B Testing
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• Continuous Testing
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• CI/CD