Using Firefox with screenshots and videos activated may hang TestCafe on a test failure

[AlexZagriychuk]

What is your Scenario?

Run TestCafe tests on Firefox with screenshots, videos, retries (quarantineMode) activated.

What is the Current behavior?

Sometimes execution hangs on the test failure.

• When it hangs, it happens because both takeScreenshot and getVideoFrameData functions called the getScreenshotData almost at the same time and then "intercepted" each other's responses, and execution hanged (probably in one of the while loops in the _getPacket firefox/marionette-client).
  Logs (_logs_with_error.log):

[TMP][1739243838950] getVideoFrameData - before getScreenshotData
[TMP][1739243838952] takeScreenshot - before getScreenshotData
[TMP] _getResponse wrong packetNumber "502" (expected "501")
[TMP] _getResponse wrong packetNumber "501" (expected "502")

What is the Expected behavior?

TestCafe execution does not hang, test fails, and has screenshots and videos in the required folder

What is the public URL of the test page? (attach your complete example)

N/A

What is your TestCafe test code?

test-cafe-bug.zip

Your complete configuration file

In the attached archive

Your complete test report

In the attached archive

Screenshots

No response

Steps to Reproduce

• Download the attached archive with the simple TestCafe repo setup to reproduce this issue
• npm i
• (Optional) add a few "debug" logs which seem to have helped me pin point the issue
  • Open node_modules/testcafe/lib/browser/provider/built-in/dedicated/firefox/marionette-client/index.js, go to the _getResponse fn and replace the while loop with:

        while (!responsePacket.body || responsePacket.body[1] !== packetNumber) {
           console.log(`[TMP] _getResponse wrong packetNumber "${responsePacket.body[1]}" (expected "${packetNumber}")`)
           responsePacket = await this._getPacket();
           console.log(`[TMP] _getResponse wrong packetNumber - responsePacket for retry (packetNumber: "${responsePacket.body[1]}"):\n${JSON.stringify(responsePacket, null, 2)}`)
       }
  

  • Open the node_modules/testcafe/lib/browser/provider/built-in/dedicated/base.js file, go to the takeScreenshot fn and add a log console.log(`[TMP][${Date.now()}] takeScreenshot - before getScreenshotData`) before the await browserClient.getScreenshotData
  • Open the node_modules/testcafe/lib/browser/provider/built-in/dedicated/firefox/index.js file, go to the getVideoFrameData fn and add a log console.log(`[TMP][${Date.now()}] getVideoFrameData - before getScreenshotData`) before return marionetteClient.getScreenshotData()
• Run the test multiple times until the execution hangs (2-10 times) rm -rf artifacts; DEBUG=testcafe:* npx testcafe firefox:headless Tests/. --page-load-timeout 15000 --skip-js-errors > _logs.log 2>&1

TestCafe version

3.7.0

Node.js version

No response

Command-line arguments

firefox:headless Tests/. --page-load-timeout 15000 --skip-js-errors

Browser name(s) and version(s)

No response

Platform(s) and version(s)

No response

Other

No response

[Bayheck]

Hello,

Your archive does not include config. Please update the archive.

In addition, please share the following information: OS and its version, Firefox version, and Node version.