test: find a new way to validate defineElement warnings without throw…

…ing off coverage

tools/base/test/define-element.test.ts

@@ -0,0 +1,61 @@
+/*
+Copyright 2020 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 } from '@open-wc/testing';
+import { stub } from 'sinon';
+
+// for window.__swc
+import '@spectrum-web-components/base';
+
+const elements = [
+    {
+        name: 'sp-color-area',
+        register: () =>
+            import('@spectrum-web-components/color-area/sp-color-area.js'),
+    },
+];
+
+const isSafari = /^((?!chrome|android).)*safari/i.test(navigator.userAgent);
+
+describe('define-element', function () {
+    this.retries(0);
+    beforeEach(function () {
+        window.__swc.verbose = true;
+        this.warn = stub(console, 'warn');
+    });
+    afterEach(function () {
+        this.warn.resetHistory();
+        window.__swc.verbose = false;
+        this.warn.restore();
+    });
+    elements.map(({ name, register }) =>
+        it('warns on redefinition', async function () {
+            const error = isSafari ? 'same tag name' : 'has already been';
+            let caughtError: Error | undefined;
+
+            customElements.define(name, class extends HTMLElement {});
+            try {
+                await register();
+            } catch (error) {
+                caughtError = error as Error;
+            }
+
+            expect(caughtError?.message ?? '').to.include(error);
+            expect(this.warn.called, 'should call console.warn()').to.be.true;
+            const spyCall = this.warn.getCall(0);
+            expect(
+                (spyCall.args.at(0) as string).includes('redefine'),
+                'message should warn about redefining an element'
+            ).to.be.true;
+        })
+    );
+});