PermutationAndCombination.test.js

import {
  factorial,
  permutation,
  combination
} from '../PermutationAndCombination'

describe('Factorial', () => {
  it('factorial(5)', () => {
    expect(factorial(5)).toBe(120)
  })
})

describe('Permutation', () => {
  it('permutation(5, 2)', () => {
    expect(permutation(5, 2)).toBe(20)
  })
})

describe('Combination', () => {
  it('combination(5, 2)', () => {
    expect(combination(5, 2)).toBe(10)
  })
})