3128: Test to show nested slots fails

test/custom-elements/index.js

@@ -105,8 +105,9 @@ describe('custom-elements', function() {
 
 			const page = await browser.newPage();
 
-			page.on('console', (type, ...args) => {
+			page.on('console', msg => {
-				console[type](...args);
+				for (let i = 0; i < msg.args().length; ++i)
+    				console[msg.type()](`${i}: ${msg.args()[i]}`);
 			});
 
 			try {

test/custom-elements/samples/nested-slots/Block.svelte

@@ -0,0 +1,3 @@
+<svelte:options tag="my-block"/>
+
+<div><slot></slot></div>

test/custom-elements/samples/nested-slots/main.svelte

@@ -0,0 +1,7 @@
+<svelte:options tag="my-app"/>
+
+<script>
+	import Block from './Block.svelte';
+</script>
+
+<Block><strong>Name</strong></Block>

test/custom-elements/samples/nested-slots/test.js

@@ -0,0 +1,13 @@
+import * as assert from 'assert';
+import './main.svelte';
+
+export default async function (target) {
+	target.innerHTML = '<my-app/>';
+	const el = target.querySelector('my-app');
+
+	const block = el.shadowRoot.children[0];
+
+	const [slot] = block.children;
+
+	assert.equal(slot.assignedNodes().length, 1);
+}