/
getCLS-test.js
558 lines (416 loc) · 17.2 KB
/
getCLS-test.js
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
/*
* Copyright 2020 Google LLC
*
* 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
*
* https://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.
*/
const assert = require('assert');
const {beaconCountIs, clearBeacons, getBeacons} = require('../utils/beacons.js');
const {browserSupportsEntry} = require('../utils/browserSupportsEntry.js');
const {afterLoad} = require('../utils/afterLoad.js');
const {imagesPainted} = require('../utils/imagesPainted.js');
const {stubForwardBack} = require('../utils/stubForwardBack.js');
const {stubVisibilityChange} = require('../utils/stubVisibilityChange.js');
describe('getCLS()', async function() {
// Retry all tests in this suite up to 2 times.
this.retries(2);
let browserSupportsCLS;
before(async function() {
browserSupportsCLS = await browserSupportsEntry('layout-shift');
});
beforeEach(async function() {
await clearBeacons();
});
it('reports the correct value on visibility hidden after shifts (reportAllChanges === false)', async function() {
if (!browserSupportsCLS) this.skip();
await browser.url('/test/cls');
// Wait until all images are loaded and rendered, then change to hidden.
await imagesPainted();
await stubVisibilityChange('hidden');
await beaconCountIs(1);
const [cls] = await getBeacons();
assert(cls.value >= 0);
assert(cls.id.match(/^v2-\d+-\d+$/));
assert.strictEqual(cls.name, 'CLS');
assert.strictEqual(cls.value, cls.delta);
assert.strictEqual(cls.entries.length, 2);
});
it('reports the correct value on page unload after shifts (reportAllChanges === false)', async function() {
if (!browserSupportsCLS) this.skip();
await browser.url('/test/cls');
// Wait until all images are loaded and rendered, then change to hidden.
await imagesPainted();
await browser.url('about:blank');
await beaconCountIs(1);
const [cls] = await getBeacons();
assert(cls.value >= 0);
assert(cls.id.match(/^v2-\d+-\d+$/));
assert.strictEqual(cls.name, 'CLS');
assert.strictEqual(cls.value, cls.delta);
assert.strictEqual(cls.entries.length, 2);
});
it('resets the session after timeout or gap elapses', async function() {
if (!browserSupportsCLS) this.skip();
await browser.url('/test/cls');
// Wait until all images are loaded and rendered.
await imagesPainted();
await browser.pause(1000);
await stubVisibilityChange('hidden');
await beaconCountIs(1);
const [cls1] = await getBeacons();
assert(cls1.value >= 0);
assert(cls1.id.match(/^v2-\d+-\d+$/));
assert.strictEqual(cls1.name, 'CLS');
assert.strictEqual(cls1.value, cls1.delta);
assert.strictEqual(cls1.entries.length, 2);
await browser.pause(1000);
await stubVisibilityChange('visible');
await clearBeacons();
// Force 2 layout shifts, totaling 0.5.
await browser.executeAsync((done) => {
document.body.style.overflow = 'hidden'; // Prevent scroll bars.
document.querySelector('main').style.left = '25vmax';
setTimeout(() => {
document.querySelector('main').style.left = '0px';
done();
}, 50);
});
await stubVisibilityChange('hidden');
await beaconCountIs(1);
const [cls2] = await getBeacons();
// The value should be exactly 0.5, but round just in case.
assert.strictEqual(Math.round(cls2.value * 100) / 100, 0.5);
assert.strictEqual(cls2.name, 'CLS');
assert.strictEqual(cls2.value, cls1.value + cls2.delta);
assert.strictEqual(cls2.entries.length, 2);
assert(cls2.id.match(/^v2-\d+-\d+$/));
await browser.pause(1000);
await stubVisibilityChange('visible');
await clearBeacons();
// Force 4 separate layout shifts, totaling 1.5.
await browser.executeAsync((done) => {
document.querySelector('main').style.left = '25vmax';
setTimeout(() => {
document.querySelector('main').style.left = '0px';
setTimeout(() => {
document.querySelector('main').style.left = '50vmax';
setTimeout(() => {
document.querySelector('main').style.left = '0px';
done();
}, 50);
}, 50);
}, 50);
});
await stubVisibilityChange('hidden');
await beaconCountIs(1);
const [cls3] = await getBeacons();
// The value should be exactly 1.5, but round just in case.
assert.strictEqual(Math.round(cls3.value * 100) / 100, 1.5);
assert.strictEqual(cls3.name, 'CLS');
assert.strictEqual(cls3.value, cls2.value + cls3.delta);
assert.strictEqual(cls3.entries.length, 4);
assert(cls3.id.match(/^v2-\d+-\d+$/));
await browser.pause(1000);
await stubVisibilityChange('visible');
await clearBeacons();
// Force 2 layout shifts, totalling 1.0 (less than the previous max).
await browser.executeAsync((done) => {
document.querySelector('main').style.left = '50vmax';
setTimeout(() => {
document.querySelector('main').style.left = '0px';
done();
}, 50);
});
// Wait a bit to ensure no beacons were sent.
await browser.pause(1000);
const beacons = await getBeacons();
assert.strictEqual(beacons.length, 0);
});
it('does not report if the browser does not support CLS', async function() {
if (browserSupportsCLS) this.skip();
await browser.url('/test/cls');
// Wait until all images are loaded and rendered, then change to hidden.
await imagesPainted();
await stubVisibilityChange('hidden');
// Wait a bit to ensure no beacons were sent.
await browser.pause(1000);
await browser.url('about:blank');
// Wait a bit to ensure no beacons were sent.
await browser.pause(1000);
const beacons = await getBeacons();
assert.strictEqual(beacons.length, 0);
});
it('reports no new values on visibility hidden after shifts (reportAllChanges === true)', async function() {
if (!browserSupportsCLS) this.skip();
await browser.url('/test/cls?reportAllChanges=1');
// Beacons should be sent as soon as layout shifts occur, wait for them.
await beaconCountIs(2);
const [cls1, cls2] = await getBeacons();
assert(cls1.value >= 0);
assert(cls1.id.match(/^v2-\d+-\d+$/));
assert.strictEqual(cls1.name, 'CLS');
assert.strictEqual(cls1.value, cls1.delta);
assert.strictEqual(cls1.entries.length, 1);
assert(cls2.value >= cls1.value);
assert.strictEqual(cls2.name, 'CLS');
assert.strictEqual(cls2.id, cls1.id);
assert.strictEqual(cls2.value, cls1.value + cls2.delta);
assert.strictEqual(cls2.entries.length, 2);
await clearBeacons();
await stubVisibilityChange('hidden');
// Wait a bit to ensure no beacons were sent.
await browser.pause(1000);
const beacons = await getBeacons();
assert.strictEqual(beacons.length, 0);
});
it('does not report if the value has not changed (reportAllChanges === true)', async function() {
if (!browserSupportsCLS) this.skip();
await browser.url('/test/cls?reportAllChanges=1');
// Beacons should be sent as soon as layout shifts occur, wait for them.
await beaconCountIs(2);
const [cls1, cls2] = await getBeacons();
assert(cls1.value >= 0);
assert(cls1.id.match(/^v2-\d+-\d+$/));
assert.strictEqual(cls1.value, cls1.delta);
assert.strictEqual(cls1.entries.length, 1);
assert(cls2.value >= cls1.value);
assert.strictEqual(cls2.name, 'CLS');
assert.strictEqual(cls2.id, cls1.id);
assert.strictEqual(cls2.value, cls1.value + cls2.delta);
assert.strictEqual(cls2.entries.length, 2);
// Unload the page after no new shifts have occurred.
await clearBeacons();
await browser.url('about:blank');
// Wait a bit to ensure no beacons were sent.
await browser.pause(1000);
const beacons = await getBeacons();
assert.strictEqual(beacons.length, 0);
});
it('continues reporting after visibilitychange (reportAllChanges === false)', async function() {
if (!browserSupportsCLS) this.skip();
await browser.url(`/test/cls`);
// Wait until all images are loaded and rendered, then change to hidden.
await imagesPainted();
await stubVisibilityChange('hidden');
await beaconCountIs(1);
const [cls1] = await getBeacons();
assert(cls1.value >= 0);
assert(cls1.delta >= 0);
assert(cls1.id.match(/^v2-\d+-\d+$/));
assert.strictEqual(cls1.name, 'CLS');
assert.strictEqual(cls1.value, cls1.delta);
assert.strictEqual(cls1.entries.length, 2);
await clearBeacons();
await stubVisibilityChange('visible');
// Wait for a frame to be painted.
await browser.executeAsync((done) => requestAnimationFrame(done));
await triggerLayoutShift();
await clearBeacons();
await stubVisibilityChange('hidden');
await beaconCountIs(1);
const [cls2] = await getBeacons();
assert(cls2.value >= cls1.value);
assert.strictEqual(cls2.name, 'CLS');
assert.strictEqual(cls2.id, cls1.id);
assert.strictEqual(cls2.value, cls1.value + cls2.delta);
assert.strictEqual(cls2.entries.length, 3);
});
it('continues reporting after visibilitychange (reportAllChanges === true)', async function() {
if (!browserSupportsCLS) this.skip();
await browser.url(`/test/cls?reportAllChanges=1`);
await beaconCountIs(2);
const [cls1, cls2] = await getBeacons();
assert(cls1.value > 0);
assert(cls1.id.match(/^v2-\d+-\d+$/));
assert.strictEqual(cls1.name, 'CLS');
assert.strictEqual(cls1.value, cls1.delta);
assert.strictEqual(cls1.entries.length, 1);
assert(cls2.value > cls1.value);
assert.strictEqual(cls2.name, 'CLS');
assert.strictEqual(cls2.id, cls1.id);
assert.strictEqual(cls2.value, cls1.value + cls2.delta);
assert.strictEqual(cls2.entries.length, 2);
// Unload the page after no new shifts have occurred.
await clearBeacons();
await stubVisibilityChange('hidden');
await stubVisibilityChange('visible');
// Wait for a frame to be painted.
await browser.executeAsync((done) => requestAnimationFrame(done));
await triggerLayoutShift();
await beaconCountIs(1);
const [cls3] = await getBeacons();
assert(cls3.value > cls2.value);
assert.strictEqual(cls3.name, 'CLS');
assert.strictEqual(cls3.id, cls2.id);
assert.strictEqual(cls3.value, cls2.value + cls3.delta);
assert.strictEqual(cls3.entries.length, 3);
});
it('continues reporting after bfcache restore (reportAllChanges === false)', async function() {
if (!browserSupportsCLS) this.skip();
await browser.url(`/test/cls`);
// Wait until all images are loaded and rendered, then go forward & back.
await imagesPainted();
await stubForwardBack();
await beaconCountIs(1);
const [cls1] = await getBeacons();
assert(cls1.value >= 0);
assert(cls1.id.match(/^v2-\d+-\d+$/));
assert.strictEqual(cls1.delta, cls1.value);
assert.strictEqual(cls1.name, 'CLS');
assert.strictEqual(cls1.value, cls1.delta);
assert.strictEqual(cls1.entries.length, 2);
await clearBeacons();
await triggerLayoutShift();
await stubForwardBack();
await beaconCountIs(1);
const [cls2] = await getBeacons();
assert(cls2.value >= 0);
assert(cls2.id.match(/^v2-\d+-\d+$/));
assert(cls2.id !== cls1.id);
assert.strictEqual(cls2.delta, cls2.value);
assert.strictEqual(cls2.name, 'CLS');
assert.strictEqual(cls2.value, cls2.delta);
assert.strictEqual(cls2.entries.length, 1);
await clearBeacons();
await triggerLayoutShift();
await stubVisibilityChange('hidden');
await beaconCountIs(1);
const [cls3] = await getBeacons();
assert(cls3.value >= 0);
assert(cls3.id.match(/^v2-\d+-\d+$/));
assert(cls3.id !== cls2.id);
assert.strictEqual(cls3.delta, cls3.value);
assert.strictEqual(cls3.name, 'CLS');
assert.strictEqual(cls3.value, cls3.delta);
assert.strictEqual(cls3.entries.length, 1);
});
it('continues reporting after bfcache restore (reportAllChanges === true)', async function() {
if (!browserSupportsCLS) this.skip();
await browser.url(`/test/cls?reportAllChanges=1`);
await beaconCountIs(2);
const [cls1, cls2] = await getBeacons();
assert(cls1.value > 0);
assert(cls1.id.match(/^v2-\d+-\d+$/));
assert.strictEqual(cls1.name, 'CLS');
assert.strictEqual(cls1.value, cls1.delta);
assert.strictEqual(cls1.entries.length, 1);
assert(cls2.value > cls1.value);
assert.strictEqual(cls2.name, 'CLS');
assert.strictEqual(cls2.id, cls1.id);
assert.strictEqual(cls2.value, cls1.value + cls2.delta);
assert.strictEqual(cls2.entries.length, 2);
await clearBeacons();
await stubForwardBack();
// Wait for a frame to be painted.
await browser.executeAsync((done) => requestAnimationFrame(done));
await triggerLayoutShift();
await beaconCountIs(1);
const [cls3] = await getBeacons();
assert(cls3.value > 0);
assert(cls3.id.match(/^v2-\d+-\d+$/));
assert(cls3.id !== cls2.id);
assert.strictEqual(cls3.name, 'CLS');
assert.strictEqual(cls3.value, cls3.delta);
assert.strictEqual(cls3.entries.length, 1);
});
it('reports zero if no layout shifts occurred on first visibility hidden (reportAllChanges === false)', async function() {
if (!browserSupportsCLS) this.skip();
await browser.url(`/test/cls?noLayoutShifts=1`);
// Wait until the page is loaded before hiding.
await afterLoad();
await stubVisibilityChange('hidden');
await beaconCountIs(1);
const [cls] = await getBeacons();
assert(cls.id.match(/^v2-\d+-\d+$/));
assert.strictEqual(cls.name, 'CLS');
assert.strictEqual(cls.value, 0);
assert.strictEqual(cls.delta, 0);
assert.strictEqual(cls.entries.length, 0);
});
it('reports zero if no layout shifts occurred on first visibility hidden (reportAllChanges === true)', async function() {
if (!browserSupportsCLS) this.skip();
await browser.url(`/test/cls?reportAllChanges=1&noLayoutShifts=1`);
// Wait until the page is loaded before hiding.
await afterLoad();
await stubVisibilityChange('hidden');
await beaconCountIs(1);
const [cls] = await getBeacons();
assert(cls.id.match(/^v2-\d+-\d+$/));
assert.strictEqual(cls.name, 'CLS');
assert.strictEqual(cls.value, 0);
assert.strictEqual(cls.delta, 0);
assert.strictEqual(cls.entries.length, 0);
});
it('reports zero if no layout shifts occurred on page unload (reportAllChanges === false)', async function() {
if (!browserSupportsCLS) this.skip();
await browser.url(`/test/cls?noLayoutShifts=1`);
// Wait until the page is loaded before navigating away.
await afterLoad();
await browser.url('about:blank');
await beaconCountIs(1);
const [cls] = await getBeacons();
assert(cls.id.match(/^v2-\d+-\d+$/));
assert.strictEqual(cls.name, 'CLS');
assert.strictEqual(cls.value, 0);
assert.strictEqual(cls.delta, 0);
assert.strictEqual(cls.entries.length, 0);
});
it('reports zero if no layout shifts occurred on page unload (reportAllChanges === true)', async function() {
if (!browserSupportsCLS) this.skip();
await browser.url(`/test/cls?noLayoutShifts=1&reportAllChanges=1`);
// Wait until the page is loaded before navigating away.
await afterLoad();
await browser.url('about:blank');
await beaconCountIs(1);
const [cls] = await getBeacons();
assert(cls.id.match(/^v2-\d+-\d+$/));
assert.strictEqual(cls.name, 'CLS');
assert.strictEqual(cls.value, 0);
assert.strictEqual(cls.delta, 0);
assert.strictEqual(cls.entries.length, 0);
});
it('does not report if the document was hidden at page load time', async function() {
await browser.url('/test/cls?hidden=1');
await stubVisibilityChange('visible');
// Wait a bit to ensure no beacons were sent.
await browser.pause(1000);
const beacons = await getBeacons();
assert.strictEqual(beacons.length, 0);
});
it('reports if the page is restored from bfcache even when the document was hidden at page load time', async function() {
if (!browserSupportsCLS) this.skip();
await browser.url('/test/cls?hidden=1');
await stubForwardBack();
// Wait for a frame to be painted.
await browser.executeAsync((done) => requestAnimationFrame(done));
await triggerLayoutShift();
await stubVisibilityChange('hidden');
await beaconCountIs(1);
const [cls] = await getBeacons();
assert(cls.value >= 0);
assert(cls.id.match(/^v2-\d+-\d+$/));
assert.strictEqual(cls.name, 'CLS');
assert.strictEqual(cls.delta, cls.value);
assert.strictEqual(cls.entries.length, 1);
});
});
let marginTop = 0;
/**
* Returns a promise that resolves once the browser window has loaded and all
* the images in the document have decoded and rendered.
* @return {Promise<void>}
*/
function triggerLayoutShift() {
return browser.execute((marginTop) => {
document.querySelector('h1').style.marginTop = marginTop + 'em';
}, ++marginTop);
}