feat add hydrating header meta testing

test/hydration/index.js

@@ -67,8 +67,16 @@ describe('hydration', () => {
 				}
 
 				const target = window.document.body;
+				const head = window.document.head;
+
 				target.innerHTML = fs.readFileSync(`${cwd}/_before.html`, 'utf-8');
 
+				let before_head;
+				try {
+					before_head = fs.readFileSync(`${cwd}/_before_head.html`, 'utf-8');
+					head.innerHTML = before_head;
+				} catch (err) {}
+
 				const snapshot = config.snapshot ? config.snapshot(target) : {};
 
 				const component = new SvelteComponent({
@@ -88,6 +96,19 @@ describe('hydration', () => {
 					}
 				}
 
+				if (before_head) {
+					try {
+						assert.htmlEqual(head.innerHTML, fs.readFileSync(`${cwd}/_after_head.html`, 'utf-8'));
+					} catch (error) {
+						if (shouldUpdateExpected()) {
+							fs.writeFileSync(`${cwd}/_after_head.html`, head.innerHTML);
+							console.log(`Updated ${cwd}/_after_head.html.`);
+						} else {
+							throw error;
+						}
+					}
+				}
+
 				if (config.test) {
 					config.test(assert, target, snapshot, component, window);
 				} else {

test/hydration/samples/head-meta-hydrate-duplicate/_after.html

@@ -0,0 +1 @@
+<div>Just a dummy page.</div>

test/hydration/samples/head-meta-hydrate-duplicate/_after_head.html

@@ -0,0 +1,4 @@
+<title>Some Title</title>
+<link rel="canonical" href="/">
+<meta name="description" content="some description">
+<meta name="keywords" content="some keywords">

test/hydration/samples/head-meta-hydrate-duplicate/_before.html

@@ -0,0 +1 @@
+<div>Just a dummy page.</div>

test/hydration/samples/head-meta-hydrate-duplicate/_before_head.html

@@ -0,0 +1,4 @@
+<title>Some Title</title>
+<link rel="canonical" href="/">
+<meta name="description" content="some description">
+<meta name="keywords" content="some keywords">

test/hydration/samples/head-meta-hydrate-duplicate/_config.js

@@ -0,0 +1,6 @@
+export default {
+	test({ assert, component, target, window }) {
+		console.log(window.document.querySelectorAll('meta'));
+		assert.equal(window.document.querySelectorAll('meta').length, 2);
+	}
+};

test/hydration/samples/head-meta-hydrate-duplicate/main.svelte

@@ -0,0 +1,8 @@
+<svelte:head>
+  <title>Some Title</title>
+  <link rel="canonical" href="/">
+  <meta name="description" content="some description">
+  <meta name="keywords" content="some keywords">
+</svelte:head>
+
+<div>Just a dummy page.</div>