add tests

packages/kit/test/apps/basics/src/routes/load/fetch-arraybuffer-b64/+page.js

@@ -0,0 +1,7 @@
+export async function load({ fetch }) {
+	const res = await fetch('/load/fetch-arraybuffer-b64/data');
+
+	return {
+		data: res.arrayBuffer()
+	};
+}

packages/kit/test/apps/basics/src/routes/load/fetch-arraybuffer-b64/+page.svelte

@@ -0,0 +1,9 @@
+<script>
+  export let data;
+
+  
+  $: arr = [...new Uint8Array(data.data)];
+
+</script>
+
+<span class="test-content">{JSON.stringify(arr)}</span>

packages/kit/test/apps/basics/src/routes/load/fetch-arraybuffer-b64/data/+server.js

@@ -0,0 +1,3 @@
+export const GET = () => {
+	return new Response(new Uint8Array([1, 2, 3, 4]));
+};

packages/kit/test/apps/basics/test/test.js

@@ -275,6 +275,22 @@ test.describe('Load', () => {
 		}
 	});
 
+	test('fetches using an arraybuffer serialized with b64', async ({ page, javaScriptEnabled }) => {
+		await page.goto('/load/fetch-arraybuffer-b64');
+
+		expect(await page.textContent('.test-content')).toBe('[1,2,3,4]');
+
+		if (!javaScriptEnabled) {
+			const payload = '{"status":200,"statusText":"","headers":{},"body":"AQIDBA=="}';
+
+			const script_content = await page.innerHTML(
+				'script[data-sveltekit-fetched][data-b64][data-url="/load/fetch-arraybuffer-b64/data"]'
+			);
+
+			expect(script_content).toBe(payload);
+		}
+	});
+
 	test('json string is returned', async ({ page }) => {
 		await page.goto('/load/relay');
 		expect(await page.textContent('h1')).toBe('42');