Merge a9d984c into 051c642

vaadin · Sep 17, 2019 · 732f906 · 732f906
2 parents 051c642 + a9d984c
commit 732f906
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diff --git a/src/vaadin-list-box.html b/src/vaadin-list-box.html
@@ -91,11 +91,20 @@
         ready() {
           super.ready();
           this.setAttribute('role', 'list');
+
+          setTimeout(this._checkImport.bind(this), 2000);
         }
 
         get _scrollerElement() {
           return this.shadowRoot.querySelector('[part="items"]');
         }
+
+        _checkImport() {
+          var item = this.querySelector('vaadin-item');
+          if (item && !(item instanceof Polymer.Element)) {
+            console.warn(`Make sure you have imported the vaadin-item element.`);
+          }
+        }
       }
 
       customElements.define(ListBoxElement.is, ListBoxElement);

diff --git a/test/import-warning-test.html b/test/import-warning-test.html
@@ -0,0 +1,57 @@
+<!doctype html>
+
+<head>
+  <meta charset="UTF-8">
+  <title>vaadin-list-box tests</title>
+  <script src="../../web-component-tester/browser.js"></script>
+  <script src="../../webcomponentsjs/webcomponents-lite.js"></script>
+  <link rel="import" href="../../test-fixture/test-fixture.html">
+  <link rel="import" href="../../polymer/polymer.html">
+  <link rel="import" href="../vaadin-list-box.html">
+</head>
+
+<body>
+  <test-fixture id="default">
+    <template>
+      <vaadin-list-box>
+        <vaadin-item>Foo</vaadin-item>
+        <vaadin-item>Bar</vaadin-item>
+      </vaadin-list-box>
+    </template>
+  </test-fixture>
+
+  <script>
+    describe(`import warning for vaadin-item`, () => {
+      let listbox;
+
+      function isV2() {
+        return window['Polymer'] && window['Polymer']['version'] && window['Polymer']['version'].indexOf('2') === 0;
+      }
+
+      beforeEach(() => listbox = fixture('default'));
+
+      it('should warn if not imported', () => {
+        sinon.stub(console, 'warn');
+        // Emulate setTimeout run from ready
+        listbox._checkImport();
+        expect(console.warn.callCount).to.equal(1);
+        console.warn.restore();
+      });
+
+      it('should not warn for present import', (done) => {
+        if (isV2()) {
+          Polymer.Base.importHref(`../../vaadin-item/vaadin-item.html`, () => {
+            sinon.stub(console, 'warn');
+            listbox._checkImport();
+            expect(console.warn.called).to.be.false;
+            console.warn.restore();
+            done();
+          });
+        } else {
+          // importHref is removed in Polymer 3 stable release, skip the test.
+          done();
+        }
+      });
+    });
+  </script>
+</body>
diff --git a/test/test-suites.js b/test/test-suites.js
@@ -1,4 +1,5 @@
 
 window.VaadinListBoxSuites = [
+  'import-warning-test.html',
   'list-box-test.html'
 ];