• Reducing bug in production
• Gain confidence in product
• Can be used as documentation

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• ✅ Unit testing
• ✅ API testing (kind of integration testing)
• ☑️ End to end testing (e2e)

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• Jest as test runner and assertion library.

  • Has both test runner (e.g. mocha) and assertion library (e.g. chai) integrated
  • We Need to familiar with matcher functions

• Supertest for testing node.js HTTP server