chore: handle hydration attributes in prerendering tests (#10181)

Svelte 4 adds these and they make tests snapshots not as predictable, so filter them out

Author: gtm-nayan

packages/kit/test/prerendering/basics/test/tests.spec.js

@@ -1,6 +1,7 @@
 import * as fs from 'node:fs';
 import { fileURLToPath } from 'node:url';
 import { assert, expect, test } from 'vitest';
+import { replace_hydration_attrs } from '../../test-utils';
 
 const build = fileURLToPath(new URL('../build', import.meta.url));
 
@@ -146,7 +147,7 @@ test('decodes paths when writing files', () => {
 });
 
 test('prerendering is set to true in root +layout.js', () => {
-	const content = read('prerendering-true.html');
+	const content = replace_hydration_attrs(read('prerendering-true.html'));
 	expect(content).toMatch('<h1>prerendering: true/true</h1>');
 });
 
@@ -198,7 +199,7 @@ test('$env - includes environment variables', () => {
 });
 
 test('prerenders a page in a (group)', () => {
-	const content = read('grouped.html');
+	const content = replace_hydration_attrs(read('grouped.html'));
 	expect(content).toMatch('<h1>grouped</h1>');
 });
 

packages/kit/test/prerendering/options/test/tests.spec.js

@@ -1,19 +1,20 @@
 import * as fs from 'node:fs';
 import { fileURLToPath } from 'node:url';
 import { assert, expect, test } from 'vitest';
+import { replace_hydration_attrs } from '../../test-utils';
 
 const build = fileURLToPath(new URL('../build', import.meta.url));
 
 /** @param {string} file */
 const read = (file) => fs.readFileSync(`${build}/${file}`, 'utf-8');
 
 test('prerenders /path-base', () => {
-	const content = read('index.html');
+	const content = replace_hydration_attrs(read('index.html'));
 	expect(content).toMatch('<h1>hello</h1>');
 });
 
 test('prerenders nested /path-base', () => {
-	const content = read('nested/index.html');
+	const content = replace_hydration_attrs(read('nested/index.html'));
 	expect(content).toMatch('<h1>nested hello</h1>');
 });
 

packages/kit/test/prerendering/test-utils.js

@@ -0,0 +1,9 @@
+/**
+ * For static content, Svelte v4 will add a data-svelte-h attribute.
+ * Replace the hash with something predictable before comparing the output.
+ *
+ * @param {string} html
+ */
+export function replace_hydration_attrs(html) {
+	return html.replace(/(\s+)data-svelte-h="svelte-\w+"/g, '');
+}