text: const {sum, subtract} = require('../math')
  
  let result, expected
  
  result = sum(3, 7)
  expected = 10
  expect(result).toBe(expected)
  
  result = subtract(7, 3)
  expected = 4
  expect(result).toBe(expected)
  
  function expect(actual) {
    return {
      toBe(expected) {
        if (actual !== expected) {
          throw new Error(`${actual} is not equal to ${expected}`)
        }
      }
    }
  }
  