fix(slider): make implicit dependency on sp-slider-handle explicit

Author: hunterloftis

packages/slider/sp-slider.ts

@@ -9,6 +9,7 @@ the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTA
 OF ANY KIND, either express or implied. See the License for the specific language
 governing permissions and limitations under the License.
 */
+import './sp-slider-handle.js'; // codify sp-slider's implicit dependency on sp-slider-handle
 import { Slider } from './src/Slider.js';
 
 customElements.define('sp-slider', Slider);

packages/slider/test/slider-handle-upgrade.test.ts

@@ -0,0 +1,42 @@
+/*
+Copyright 2021 Adobe. All rights reserved.
+This file is licensed to you under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License. You may obtain a copy
+of the License at http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software distributed under
+the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+OF ANY KIND, either express or implied. See the License for the specific language
+governing permissions and limitations under the License.
+*/
+
+import { expect, fixture, html } from '@open-wc/testing';
+import '../sp-slider.js';
+import { Slider } from '../src/Slider.js';
+
+describe('Slider - upgrade order', () => {
+    it('loads both handles when document imports sp-slider-handle after sp-slider', async () => {
+        const el = await fixture<Slider>(html`
+            <sp-slider variant="range" step="1" min="0" max="255">
+                Output Levels
+                <sp-slider-handle
+                    slot="handle"
+                    name="min"
+                    label="Minimum"
+                    value="5"
+                ></sp-slider-handle>
+                <sp-slider-handle
+                    slot="handle"
+                    name="max"
+                    label="Maximum"
+                    value="250"
+                ></sp-slider-handle>
+            </sp-slider>
+        `);
+
+        import('../sp-slider-handle.js');
+
+        const handles = el.shadowRoot.querySelectorAll('.handle');
+        expect(handles).to.have.lengthOf(2);
+    });
+});