Test-driving the page component

It’s time to create the page component that exists for the route. As ever, we’ll start with a test:

1. Create the src/routes/birthdays/page.test.js file and add the following imports. The last of these is for the page component itself. Because SvelteKit expects the component for a route to exist in a file named +page.svelte, we may as well give the component the name Page (that is what it is, after all):

   import { describe, it, expect } from 'vitest';
   import {
     render,
     screen
   } from '@testing-library/svelte';
   import Page from './+page.svelte';

2. Next, let’s write out the test. The key part here is that Page gets passed a data prop, which needs to match the structure of our load function. In the actual runtime environment, SvelteKit will invoke the load function and then render the component in +page.svelte with the data prop set to the result of the load function:

   describe...