[BUG] Webkit and Firefox do not respect locale setting

Context:

• Playwright Version: latest
• Operating System: Win10
• Node.js version: LTS
• Browser: Webkit, Firefox
• Extra: [any specific details about your environment]

Describe the bug Our frontend application is built using Angular.

Every request it sends to the backend must have Accept-Language header, with short language value, e.g. cs. NOT cs-CZ - that is considered invalid, and backend will return HTTP error.

I have two issues:

• when locale is not explicitly set in the configuration, then Webkit and Firefox ignore cs value which should be set by application under test, and set en-US for Accept-Language header value.

• when locale is explicitly set - either in config file, or using test.use() in the test, then it:

  • in the trace console log shows, that header value is cs, BUT backend logs shows, that in reality it sends cs, cs-CZ.
  • Firefox will start sending correct request header intermittently, or after calling page.reload()
  • Webkit will be still bugged

This is currently a blocker for testing on these two browsers, since without backend data application cannot render needed content.

[pavelfeldman]

I think we have enough information to act.

[Mone71]

Thanks