add test

packages/svelte/tests/runtime-runes/samples/derived-server-memoization/_config.js

@@ -0,0 +1,3 @@
+import { test } from '../../test';
+
+export default test({});

packages/svelte/tests/runtime-runes/samples/derived-server-memoization/main.svelte

@@ -0,0 +1,29 @@
+<script>
+	import { reset, increment, get, count } from './state.svelte.js';
+
+	reset();
+	get();
+	increment();
+	get();
+
+	// non-render-bound deriveds recalculate
+	if (count !== 2) {
+		throw new Error(`count was ${count}`);
+	}
+
+	let local_count = 0;
+
+	let s = $state(0);
+	let d = $derived.by(() => {
+		local_count += 1;
+		return s * 2;
+	});
+
+	d;
+	d;
+
+	// render-bound deriveds do not
+	if (local_count !== 1) {
+		throw new Error(`local_count was ${local_count}`);
+	}
+</script>

packages/svelte/tests/runtime-runes/samples/derived-server-memoization/state.svelte.js

@@ -0,0 +1,20 @@
+let s = $state(0);
+let d = $derived.by(() => {
+	count += 1;
+	return s * 2;
+});
+
+export let count = 0;
+
+export function reset() {
+	count = 0;
+	s = 0;
+}
+
+export function increment() {
+	s += 1;
+}
+
+export function get() {
+	return d;
+}