Jest is a popular JavaScript testing framework developed by Facebook, widely used for unit testing, integration testing, and test-driven development (TDD). It’s known for its simplicity, speed, and built-in features like mocking, snapshot testing, and code coverage.

Key Features 📋

  • Zero-configuration setup ✅
  • Automatic mocking 🧠
  • Snapshot testing 📸 (detects unintended changes in component output)
  • Code coverage reporting 📊
  • Parallel test execution ⚡

How to Use 🚀

  1. Install Jest 
    npm install --save-dev jest
  2. Write Tests
    Create files ending with .test.js or .spec.js and use describe, it, and expect for test structure.
  3. Run Tests
    Use the command: 
    npx jest

Example: Testing a Function 🧪

// Example: sum.test.js
test('adds 1 + 2 to equal 3', () => {
  expect(sum(1, 2)).toBe(3);
});

Extend Your Knowledge 📚

For a deeper dive into Jest basics, check out our Jest Getting Started Guide.

Jest_Framework

Jest also integrates seamlessly with React, Node.js, and other JavaScript ecosystems. Explore its configuration options to tailor it to your project needs! 🛠️