TDD

Test specifications can read like a sentence

1. shoppintcart-test.js 🔒

   describe('The shopping cart', function() {
   	describe('subtotal should', function() {
   		it('be zero if no items are passed in', function() {
   			// Arrange
   			const shoppingCart = new ShoppingCart();
   			// Act
   			const subtotal = shoppingCart.subtotal;
   			// Assert
   			assert.equal(subtotal, 0);
   		});
   	});
   });

   Here’s an example from David Tang’s course on testing with Mocha in Node.js that uses the arrange/act/assert pattern.

   Each testing framework will have different lingo and method names. This example is just an outline. It doesn’t actually import the ShoppingCart. So maybe there need to be a few more parts of this pattern.

2. shoppintcart-test.js 🔒

   // Arrange everything you'll need below
   import { ShoppingCart } from './services/ShoppingCart.js';
   
   describe('The shopping cart', function() {
   	describe('subtotal should', function() {
   		it('be zero if no items are passed in', function() {
   			// Arrange
   			const shoppingCart = new ShoppingCart();
   			// Act
   			const subtotal = shoppingCart.subtotal;
   			// Assert
   			assert.equal(subtotal, 0);
   		});
   	});
   });