245 lines
		
	
	
		
			8.0 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
			
		
		
	
	
			245 lines
		
	
	
		
			8.0 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
| import LazyLoader from '~/lazy_loader';
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| import { TEST_HOST } from './test_constants';
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| import scrollIntoViewPromise from './helpers/scroll_into_view_promise';
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| import waitForPromises from './helpers/wait_for_promises';
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| import waitForAttributeChange from './helpers/wait_for_attribute_change';
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| 
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| const execImmediately = callback => {
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|   callback();
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| };
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| 
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| describe('LazyLoader', function() {
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|   let lazyLoader = null;
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| 
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|   preloadFixtures('issues/issue_with_comment.html');
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| 
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|   describe('without IntersectionObserver', () => {
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|     beforeEach(function() {
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|       loadFixtures('issues/issue_with_comment.html');
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| 
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|       lazyLoader = new LazyLoader({
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|         observerNode: 'foobar',
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|       });
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| 
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|       spyOn(LazyLoader, 'supportsIntersectionObserver').and.callFake(() => false);
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| 
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|       spyOn(LazyLoader, 'loadImage').and.callThrough();
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| 
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|       spyOn(window, 'requestAnimationFrame').and.callFake(execImmediately);
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|       spyOn(window, 'requestIdleCallback').and.callFake(execImmediately);
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| 
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|       // Doing everything that happens normally in onload
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|       lazyLoader.register();
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|     });
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| 
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|     afterEach(() => {
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|       lazyLoader.unregister();
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|     });
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| 
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|     it('should copy value from data-src to src for img 1', function(done) {
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|       const img = document.querySelectorAll('img[data-src]')[0];
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|       const originalDataSrc = img.getAttribute('data-src');
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| 
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|       Promise.all([scrollIntoViewPromise(img), waitForAttributeChange(img, ['data-src', 'src'])])
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|         .then(() => {
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|           expect(LazyLoader.loadImage).toHaveBeenCalled();
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|           expect(img.getAttribute('src')).toBe(originalDataSrc);
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|           expect(img).toHaveClass('js-lazy-loaded');
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|           done();
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|         })
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|         .catch(done.fail);
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|     });
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| 
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|     it('should lazy load dynamically added data-src images', function(done) {
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|       const newImg = document.createElement('img');
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|       const testPath = `${TEST_HOST}/img/testimg.png`;
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|       newImg.className = 'lazy';
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|       newImg.setAttribute('data-src', testPath);
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|       document.body.appendChild(newImg);
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| 
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|       Promise.all([
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|         scrollIntoViewPromise(newImg),
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|         waitForAttributeChange(newImg, ['data-src', 'src']),
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|       ])
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|         .then(() => {
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|           expect(LazyLoader.loadImage).toHaveBeenCalledWith(newImg);
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|           expect(newImg.getAttribute('src')).toBe(testPath);
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|           expect(newImg).toHaveClass('js-lazy-loaded');
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|           done();
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|         })
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|         .catch(done.fail);
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|     });
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| 
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|     it('should not alter normal images', function(done) {
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|       const newImg = document.createElement('img');
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|       const testPath = `${TEST_HOST}/img/testimg.png`;
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|       newImg.setAttribute('src', testPath);
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|       document.body.appendChild(newImg);
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| 
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|       scrollIntoViewPromise(newImg)
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|         .then(waitForPromises)
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|         .then(() => {
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|           expect(LazyLoader.loadImage).not.toHaveBeenCalledWith(newImg);
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|           expect(newImg).not.toHaveClass('js-lazy-loaded');
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|           done();
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|         })
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|         .catch(done.fail);
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|     });
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| 
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|     it('should not load dynamically added pictures if content observer is turned off', done => {
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|       lazyLoader.stopContentObserver();
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| 
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|       const newImg = document.createElement('img');
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|       const testPath = `${TEST_HOST}/img/testimg.png`;
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|       newImg.className = 'lazy';
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|       newImg.setAttribute('data-src', testPath);
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|       document.body.appendChild(newImg);
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| 
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|       scrollIntoViewPromise(newImg)
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|         .then(waitForPromises)
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|         .then(() => {
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|           expect(LazyLoader.loadImage).not.toHaveBeenCalledWith(newImg);
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|           expect(newImg).not.toHaveClass('js-lazy-loaded');
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|           done();
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|         })
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|         .catch(done.fail);
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|     });
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| 
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|     it('should load dynamically added pictures if content observer is turned off and on again', done => {
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|       lazyLoader.stopContentObserver();
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|       lazyLoader.startContentObserver();
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| 
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|       const newImg = document.createElement('img');
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|       const testPath = `${TEST_HOST}/img/testimg.png`;
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|       newImg.className = 'lazy';
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|       newImg.setAttribute('data-src', testPath);
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|       document.body.appendChild(newImg);
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| 
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|       Promise.all([
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|         scrollIntoViewPromise(newImg),
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|         waitForAttributeChange(newImg, ['data-src', 'src']),
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|       ])
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|         .then(waitForPromises)
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|         .then(() => {
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|           expect(LazyLoader.loadImage).toHaveBeenCalledWith(newImg);
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|           expect(newImg).toHaveClass('js-lazy-loaded');
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|           done();
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|         })
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|         .catch(done.fail);
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|     });
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|   });
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| 
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|   describe('with IntersectionObserver', () => {
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|     beforeEach(function() {
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|       loadFixtures('issues/issue_with_comment.html');
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| 
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|       lazyLoader = new LazyLoader({
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|         observerNode: 'foobar',
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|       });
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| 
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|       spyOn(LazyLoader, 'loadImage').and.callThrough();
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| 
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|       spyOn(window, 'requestAnimationFrame').and.callFake(execImmediately);
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|       spyOn(window, 'requestIdleCallback').and.callFake(execImmediately);
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| 
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|       // Doing everything that happens normally in onload
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|       lazyLoader.register();
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|     });
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| 
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|     afterEach(() => {
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|       lazyLoader.unregister();
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|     });
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| 
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|     it('should copy value from data-src to src for img 1', function(done) {
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|       const img = document.querySelectorAll('img[data-src]')[0];
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|       const originalDataSrc = img.getAttribute('data-src');
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| 
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|       Promise.all([scrollIntoViewPromise(img), waitForAttributeChange(img, ['data-src', 'src'])])
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|         .then(() => {
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|           expect(LazyLoader.loadImage).toHaveBeenCalledWith(img);
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|           expect(img.getAttribute('src')).toBe(originalDataSrc);
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|           expect(img).toHaveClass('js-lazy-loaded');
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|           done();
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|         })
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|         .catch(done.fail);
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|     });
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| 
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|     it('should lazy load dynamically added data-src images', function(done) {
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|       const newImg = document.createElement('img');
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|       const testPath = `${TEST_HOST}/img/testimg.png`;
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|       newImg.className = 'lazy';
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|       newImg.setAttribute('data-src', testPath);
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|       document.body.appendChild(newImg);
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| 
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|       Promise.all([
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|         scrollIntoViewPromise(newImg),
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|         waitForAttributeChange(newImg, ['data-src', 'src']),
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|       ])
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|         .then(() => {
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|           expect(LazyLoader.loadImage).toHaveBeenCalledWith(newImg);
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|           expect(newImg.getAttribute('src')).toBe(testPath);
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|           expect(newImg).toHaveClass('js-lazy-loaded');
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|           done();
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|         })
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|         .catch(done.fail);
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|     });
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| 
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|     it('should not alter normal images', function(done) {
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|       const newImg = document.createElement('img');
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|       const testPath = `${TEST_HOST}/img/testimg.png`;
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|       newImg.setAttribute('src', testPath);
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|       document.body.appendChild(newImg);
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| 
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|       scrollIntoViewPromise(newImg)
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|         .then(waitForPromises)
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|         .then(() => {
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|           expect(LazyLoader.loadImage).not.toHaveBeenCalledWith(newImg);
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|           expect(newImg).not.toHaveClass('js-lazy-loaded');
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|           done();
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|         })
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|         .catch(done.fail);
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|     });
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| 
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|     it('should not load dynamically added pictures if content observer is turned off', done => {
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|       lazyLoader.stopContentObserver();
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| 
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|       const newImg = document.createElement('img');
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|       const testPath = `${TEST_HOST}/img/testimg.png`;
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|       newImg.className = 'lazy';
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|       newImg.setAttribute('data-src', testPath);
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|       document.body.appendChild(newImg);
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| 
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|       scrollIntoViewPromise(newImg)
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|         .then(waitForPromises)
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|         .then(() => {
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|           expect(LazyLoader.loadImage).not.toHaveBeenCalledWith(newImg);
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|           expect(newImg).not.toHaveClass('js-lazy-loaded');
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|           done();
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|         })
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|         .catch(done.fail);
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|     });
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| 
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|     it('should load dynamically added pictures if content observer is turned off and on again', done => {
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|       lazyLoader.stopContentObserver();
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|       lazyLoader.startContentObserver();
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| 
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|       const newImg = document.createElement('img');
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|       const testPath = `${TEST_HOST}/img/testimg.png`;
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|       newImg.className = 'lazy';
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|       newImg.setAttribute('data-src', testPath);
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|       document.body.appendChild(newImg);
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| 
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|       Promise.all([
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|         scrollIntoViewPromise(newImg),
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|         waitForAttributeChange(newImg, ['data-src', 'src']),
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|       ])
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|         .then(() => {
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|           expect(LazyLoader.loadImage).toHaveBeenCalledWith(newImg);
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|           expect(newImg).toHaveClass('js-lazy-loaded');
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|           done();
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|         })
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|         .catch(done.fail);
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|     });
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|   });
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| });
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