testcafe-browser-provider-chromejpeg

TestCafe browser provider for Chrome with JPEG screenshot support

Background

• Chrome's Page.captureScreenshot() is on average 5 times faster for JPEG as opposed to PNG. This has significant benefits when comparing screenshots for a large test suite.
• TestCafe's PNG postprocessing is slow (follow the original issue here).

Solution

• Using JPEG format in Chrome and ignoring TestCafe's postprocessing significantly improves performance.
• JPEG quality is set 100 to minimise the artifacts. Artifacts should not matter much for JPEG to JPEG comparison on the same platform. The comparison should be always done on the same environment (e.g. in Docker).
• Fragment screenshots are not supported.

Usage

Install:

npm install testcafe-browser-provider-chromejpeg

Run:

testcafe chromejpeg:chrome my-test.js

Known issues

Due to TestCafe being unable to process JPEGs, the following warning is expected at the end of test execution.

 Warnings (1):
 --
  Was unable to take a screenshot due to an error.

  Error: Invalid file signature
      at module.exports.Parser._parseSignature
      ...