providing pageRanges in payload for '/print' returns base64 for total pages

[harsha509]

System

• Version: 0.28.0, 0.27.0
• Platform: macOS
• Firefox: 82.0.3 (64-bit)
• Selenium: NA

Testcase

As this is still not implemented in Selenium Alpha, i have created a git repo to reproduce issue. Here is the git repo and instructions documented in readme

https://github.com/JS31096/printPageIssueFirefox

Stacktrace

No stack trace, the base64 gets generated successfully for total pages which not the expected result.
Providing pageRanges:["1-2"] for 8 pages gives base64 for 8 pages.

Note: as base64 gets generated successfully, i have saved the base64 to pdf and tested visually.

[jgraham]

https://bugzilla.mozilla.org/show_bug.cgi?id=1678347