Fix props-after-create test

test/custom-elements/samples/props-after-create/test.js

@@ -2,17 +2,22 @@ import * as assert from 'assert';
 import CustomElement from './main.svelte';
 
 export default async function (target) {
+
+	// initialize without options to simulate instantiation within HTML
 	const el = new CustomElement();
 
 	assert.equal(el.outerHTML, '<custom-element></custom-element>');
 
-	// const el = target.querySelector('custom-element');
+	el.items = ['a', 'b', 'c'];
+	const p0 = el.shadowRoot.querySelector('p');
 
-	assert.equal(el.shadowRoot, undefined);
+	// shouldn't be instantitated yet
+	assert.equal(p0, undefined);
 
-	el.items = ['a', 'b', 'c'];
-	const [p1, p2] = el.shadowRoot.querySelectorAll('p');
+	// simulate adding to DOM to trigger setup
+	el.connectedCallback();
 
+	const [p1, p2] = el.shadowRoot.querySelectorAll('p');
 	assert.equal(p1.textContent, '3 items');
 	assert.equal(p2.textContent, 'a, b, c');