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Source code for https://gomakethings.com/dont-test-implementation-details/
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| const calculator = (function () { | |
| /** | |
| * Remove non-numeric strings from the array | |
| * @param {Array} nums The original array | |
| * @return {Array} The cleaned array | |
| */ | |
| function cleanNumbers (nums) { | |
| let cleaned = []; | |
| for (let num of nums) { | |
| num = parseFloat(num); | |
| if (Number.isNaN(num)) continue; | |
| cleaned.push(num); | |
| } | |
| return cleaned; | |
| } | |
| /** | |
| * Add two or more numbers together | |
| * @param {...Numbers} nums The numbers to add together | |
| * @return Number The total | |
| */ | |
| function add (...nums) { | |
| nums = cleanNumbers(nums); | |
| let total = nums.length ? nums.shift() : 0; | |
| for (let num of nums) { | |
| // num = parseFloat(num); | |
| // if (Number.isNaN(num)) continue; | |
| total = total + num; | |
| } | |
| return total; | |
| } | |
| /** | |
| * Add two or more numbers together | |
| * @param {...Numbers} nums The numbers to add together | |
| * @return Number The total | |
| */ | |
| function subtract (...nums) { | |
| nums = cleanNumbers(nums); | |
| let total = nums.length ? nums.shift() : 0; | |
| for (let num of nums) { | |
| // num = parseFloat(num); | |
| // if (Number.isNaN(num)) continue; | |
| total = total - num; | |
| } | |
| return total; | |
| } | |
| /** | |
| * Add two or more numbers together | |
| * @param {...Numbers} nums The numbers to add together | |
| * @return Number The total | |
| */ | |
| function multiply (...nums) { | |
| nums = cleanNumbers(nums); | |
| let total = nums.length ? nums.shift() : 0; | |
| for (let num of nums) { | |
| // num = parseFloat(num); | |
| // if (Number.isNaN(num)) continue; | |
| total = total * num; | |
| } | |
| return total; | |
| } | |
| /** | |
| * Add two or more numbers together | |
| * @param {...Numbers} nums The numbers to add together | |
| * @return Number The total | |
| */ | |
| function divide (...nums) { | |
| nums = cleanNumbers(nums); | |
| let total = nums.length ? nums.shift() : 0; | |
| for (let num of nums) { | |
| // num = parseFloat(num); | |
| // if (Number.isNaN(num)) continue; | |
| total = total / num; | |
| } | |
| return total; | |
| } | |
| return {add, subtract, multiply, divide}; | |
| })(); |
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| <!DOCTYPE html> | |
| <html lang="en"> | |
| <head> | |
| <meta charset="utf-8" /> | |
| <title>Mocha Tests</title> | |
| <meta name="viewport" content="width=device-width, initial-scale=1.0" /> | |
| <link rel="stylesheet" href="https://unpkg.com/mocha/mocha.css" /> | |
| </head> | |
| <body> | |
| <div id="mocha"></div> | |
| <script src="https://unpkg.com/chai@4/chai.js"></script> | |
| <script src="https://unpkg.com/mocha/mocha.js"></script> | |
| <script class="mocha-init"> | |
| mocha.setup('bdd'); | |
| mocha.checkLeaks(); | |
| window.addEventListener('load', function () { | |
| mocha.run(); | |
| }); | |
| </script> | |
| <script src="calculator.js"></script> | |
| <script src="test.calculator.js"></script> | |
| </body> | |
| </html> |
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| const {expect} = chai; | |
| const {add, subtract, multiply, divide} = calculator; | |
| describe('The calculator.js library', function () { | |
| describe('the add() method', function () { | |
| it('Should add two or more numbers together', function () { | |
| expect(add(4, 6, 8)).to.equal(18); | |
| }); | |
| it('Should return the original value when one number is provided', function () { | |
| expect(add(42)).to.equal(42); | |
| }); | |
| it('Should return 0 if no numbers are provided', function () { | |
| expect(add()).to.equal(0); | |
| }); | |
| it('Should skip non-numeric values', function () { | |
| expect(add(4, 6, 'abc')).to.equal(10); | |
| expect(add(4, 6, '8')).to.equal(18); | |
| }); | |
| }); | |
| describe('the subtract() method', function () { | |
| it('Should subtract two or more numbers', function () { | |
| expect(subtract(8, 3, 2)).to.equal(3); | |
| }); | |
| it('Should return the original value when one number is provided', function () { | |
| expect(subtract(42)).to.equal(42); | |
| }); | |
| it('Should return 0 if no numbers are provided', function () { | |
| expect(subtract()).to.equal(0); | |
| }); | |
| it('Should skip non-numeric values', function () { | |
| expect(subtract(8, 3, 'abc')).to.equal(5); | |
| expect(subtract(8, 3, '2')).to.equal(3); | |
| }); | |
| }); | |
| describe('the multiply() method', function () { | |
| it('Should multiply two or more numbers', function () { | |
| expect(multiply(8, 3, 2)).to.equal(48); | |
| }); | |
| it('Should return the original value when one number is provided', function () { | |
| expect(multiply(42)).to.equal(42); | |
| }); | |
| it('Should return 0 if no numbers are provided', function () { | |
| expect(multiply()).to.equal(0); | |
| }); | |
| it('Should skip non-numeric values', function () { | |
| expect(multiply(8, 3, 'abc')).to.equal(24); | |
| expect(multiply(8, 3, '2')).to.equal(48); | |
| }); | |
| }); | |
| describe('the divide() method', function () { | |
| it('Should divide two or more numbers', function () { | |
| expect(divide(42, 3, 2)).to.equal(7); | |
| }); | |
| it('Should return the original value when one number is provided', function () { | |
| expect(divide(42)).to.equal(42); | |
| }); | |
| it('Should return 0 if no numbers are provided', function () { | |
| expect(divide()).to.equal(0); | |
| }); | |
| it('Should skip non-numeric values', function () { | |
| expect(divide(42, 3, 'abc')).to.equal(14); | |
| expect(divide(42, 3, '2')).to.equal(7); | |
| }); | |
| }); | |
| }); |
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