Jassif Team Institution

npm install --save-dev jest

utils/math.js

function sum(a, b) {
  if (typeof a !== 'number' || typeof b !== 'number') {
    throw new Error('Both arguments must be numbers');
  }
  return a + b;
}

function divide(a, b) {
  if (b === 0) {
    throw new Error('Division by zero');
  }
  return a / b;
}

module.exports = { sum, divide };

__tests__/math.test.js

const { sum, divide } = require('../utils/math');

describe('Math utilities', () => {
  describe('sum()', () => {
    it('should add two numbers correctly', () => {
      expect(sum(1, 2)).toBe(3);
      expect(sum(-1, 1)).toBe(0);
    });

    it('should throw error for non-number inputs', () => {
      expect(() => sum('1', 2)).toThrow('Both arguments must be numbers');
    });
  });

  describe('divide()', () => {
    it('should divide two numbers correctly', () => {
      expect(divide(10, 2)).toBe(5);
    });

    it('should throw error when dividing by zero', () => {
      expect(() => divide(10, 0)).toThrow('Division by zero');
    });
  });
});

# Run all tests
npx jest

# Run tests in watch mode
npx jest --watch

# Run tests matching a specific pattern
npx jest -t "math utilities"

# Generate coverage report
npx jest --coverage

npm install --save-dev mocha chai

test/math.test.js

const { expect } = require('chai');
const { sum, divide } = require('../utils/math');

describe('Math Utilities', () => {
  describe('sum()', () => {
    it('should return the sum of two numbers', () => {
      expect(sum(1, 2)).to.equal(3);
      expect(sum(-1, 1)).to.equal(0);
    });

    it('should throw error for non-number inputs', () => {
      expect(() => sum('1', 2)).to.throw('Both arguments must be numbers');
    });
  });

  describe('divide()', () => {
    it('should divide two numbers correctly', () => {
      expect(divide(10, 2)).to.equal(5);
    });

    it('should throw error when dividing by zero', () => {
      expect(() => divide(10, 0)).to.throw('Division by zero');
    });
  });
});

# Add to package.json
"scripts": {
  "test": "mocha"
}

# Run tests
npm test

# Run with specific reporter
npx mocha --reporter nyan

# Run with coverage
npx nyc mocha

npm install -D vitest

math.test.js

import { describe, it, expect } from 'vitest';
import { sum, divide } from './math.js';

describe('Math Utilities', () => {
  it('should add numbers', () => {
    expect(sum(1, 2)).toBe(3);
  });

  it('should throw error for invalid inputs', () => {
    expect(() => sum('1', 2)).toThrow('Both arguments must be numbers');
  });
});