[BUG] HTML report crashes if diff snapshot does not exists

[fcollonval]

Context:

System:

• OS: Linux 5.10 Debian GNU/Linux 11 (bullseye) 11 (bullseye)
• Memory: 17.90 GB / 31.09 GB
• Container: Yes

Binaries:

• Node: 15.14.0 - ~/miniconda3/envs/jlab-dev/bin/node
• Yarn: 1.21.1 - ~/projects/jupyterlab/node_modules/.bin/yarn
• npm: 7.7.6 - ~/miniconda3/envs/jlab-dev/bin/npm

Languages:

• Bash: 5.1.8 - /usr/bin/bash

• @playwright/test 1.14.0

Describe the bug

I know the feature has not been advertised. But as the code made it to the latest release, I'm testing the HTML reporter 😃

In case an image snapshot is changing size between the expected and the actual versions, no diff is generated. However the reporter is looking for one (see trace below):

Error: ENOENT: no such file or directory, copyfile '/home/fcollonval/projects/jupyterlab/ui-tests/test-results/tests-menus-Open-menu-item-Settings-Language/opened-menu-settings-language-diff.png' -> '/home/fcollonval/projects/jupyterlab/ui-tests/playwright-report/resources/733badcdf57e4b033609e15541f3428fb597845e.png'
    at Object.copyFileSync (node:fs:2068:3)
    at HtmlReporter._createAttachments (/home/fcollonval/projects/jupyterlab/node_modules/@playwright/test/lib/test/reporters/html.js:153:21)
    at HtmlReporter._serializeResult (/home/fcollonval/projects/jupyterlab/node_modules/@playwright/test/lib/test/reporters/html.js:139:31)
    at /home/fcollonval/projects/jupyterlab/node_modules/@playwright/test/lib/test/reporters/html.js:126:61
    at Array.map (<anonymous>)
    at HtmlReporter._serializeTest (/home/fcollonval/projects/jupyterlab/node_modules/@playwright/test/lib/test/reporters/html.js:126:47)
    at /home/fcollonval/projects/jupyterlab/node_modules/@playwright/test/lib/test/reporters/html.js:110:58
    at Array.map (<anonymous>)
    at HtmlReporter._serializeSuite (/home/fcollonval/projects/jupyterlab/node_modules/@playwright/test/lib/test/reporters/html.js:110:44)
    at processTicksAndRejections (node:internal/process/task_queues:94:5)
    at async Promise.all (index 0)
    at HtmlReporter._serializeSuite (/home/fcollonval/projects/jupyterlab/node_modules/@playwright/test/lib/test/reporters/html.js:109:15)
    at async Promise.all (index 0)
    at HtmlReporter._serializeSuite (/home/fcollonval/projects/jupyterlab/node_modules/@playwright/test/lib/test/reporters/html.js:109:15)
    at async Promise.all (index 0) {
  errno: -2,
  syscall: 'copyfile',
  code: 'ENOENT',
  path: '/home/fcollonval/projects/jupyterlab/ui-tests/test-results/tests-menus-Open-menu-item-Settings-Language/opened-menu-settings-language-diff.png',
  dest: '/home/fcollonval/projects/jupyterlab/ui-tests/playwright-report/resources/733badcdf57e4b033609e15541f3428fb597845e.png'
}
error Command failed with exit code 1.

Source folder content:

$ ll /home/fcollonval/projects/jupyterlab/ui-tests/test-results/tests-menus-Open-menu-item-Settings-Language/
-rw-r--r--  1 fcollonval fcollonval 202864 Aug 18 16:53 4a4d29990d874c00beae9a8403dfeaf1.webm
-rw-r--r--  1 fcollonval fcollonval   3556 Aug 18 16:53 opened-menu-settings-language-actual.png
-rw-r--r--  1 fcollonval fcollonval    921 Aug 18 16:53 opened-menu-settings-language-expected.png