tests and lints

src/utils/pause-helper.js

@@ -14,13 +14,9 @@
  * limitations under the License.
  */
 
-import {
-  observeContentSize,
-  unobserveContentSize,
-} from './size-observer';
+import {observeContentSize, unobserveContentSize} from './size-observer';
 
 export class PauseHelper {
-
   /**
    * @param {!AmpElement} element
    */

test/unit/utils/test-pause-helper.js

@@ -0,0 +1,69 @@
+/**
+ * Copyright 2021 The AMP HTML Authors. All Rights Reserved.
+ *
+ * Licensed 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 CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {PauseHelper} from '../../../src/utils/pause-helper';
+import {installResizeObserverStub} from '../../../testing/resize-observer-stub';
+
+describes.realWin('PauseHelper', {}, (env) => {
+  let win, doc;
+  let resizeObserverStub;
+  let element;
+  let helper;
+
+  beforeEach(() => {
+    win = env.win;
+    doc = win.document;
+    resizeObserverStub = installResizeObserverStub(env.sandbox, win);
+
+    element = doc.createElement('amp-test');
+    element.pause = () => {};
+    env.sandbox.stub(element, 'pause');
+
+    helper = new PauseHelper(element);
+  });
+
+  it('should start observing', () => {
+    expect(resizeObserverStub.isObserved(element)).to.be.false;
+    helper.updatePlaying(true);
+    expect(resizeObserverStub.isObserved(element)).to.be.true;
+
+    resizeObserverStub.notifySync({
+      target: element,
+      contentRect: {width: 100, height: 100},
+    });
+    expect(element.pause).to.not.be.called;
+  });
+
+  it('should start observing and pause', () => {
+    expect(resizeObserverStub.isObserved(element)).to.be.false;
+    helper.updatePlaying(true);
+    expect(resizeObserverStub.isObserved(element)).to.be.true;
+
+    resizeObserverStub.notifySync({
+      target: element,
+      contentRect: {width: 0, height: 0},
+    });
+    expect(element.pause).to.be.calledOnce;
+  });
+
+  it('should unobserve', () => {
+    helper.updatePlaying(true);
+    expect(resizeObserverStub.isObserved(element)).to.be.true;
+
+    helper.updatePlaying(false);
+    expect(resizeObserverStub.isObserved(element)).to.be.false;
+  });
+});