wip getLoadingComplete test for dialog

components/dialog/test/dialog.test.js

@@ -1,8 +1,9 @@
 import '../dialog.js';
 import { expect, fixture, oneEvent, runConstructor } from '@brightspace-ui/testing';
+import { html, LitElement } from 'lit';
 import { createMessage } from '../../../mixins/property-required/property-required-mixin.js';
 import { getComposedActiveElement } from '../../../helpers/focus.js';
-import { html } from 'lit';
+import { spy } from 'sinon';
 
 describe('d2l-dialog', () => {
 
@@ -80,4 +81,44 @@ describe('d2l-dialog', () => {
 
 	});
 
+	class DelayedElement extends LitElement {
+		render() {
+			return html`<div class="delayed-div"></div>`;
+		}
+
+		async getLoadingComplete() {
+			const newChild = document.createElement('div');
+			newChild.className = 'added-child';
+			newChild.textContent = 'New addition to the family!';
+			this.shadowRoot.appendChild(newChild);
+			await new Promise(r => setTimeout(r, 100));
+		}
+	}
+	customElements.define('delayed-elem', DelayedElement);
+
+	describe('getLoadingComplete', () => {
+
+		it('should wait for child component\'s getLoadingComplete before resizing', async() => {
+
+			const el = await fixture(html`
+				<d2l-dialog>
+					<delayed-elem></delayed-elem>
+				</d2l-dialog>
+			`);
+
+			const delayedComponent = el.querySelector('delayed-elem');
+			const mixinProto = Object.getPrototypeOf(el).__proto__;
+			const resizeSpy = spy(mixinProto, 'resize');
+
+			el.opened = true;
+			await oneEvent(el, 'd2l-dialog-open');
+			el.asyncState = 'complete';
+
+			expect(resizeSpy.called).to.be.false;
+			await delayedComponent.getLoadingComplete();
+			expect(resizeSpy.calledOnce).to.be.true;
+		});
+
+	});
+
 });