[CUPS Test Page] Print Test Page with optional Media Size

[Caixicui]

Hi,
When setting different Media Size, all the Test Pages are same.

Open localhost:631, and configure the printer with A5 Media Size,
and other options are default. The result is same with setting option A4 Media Size.

But When I set Media Size Option to A5 and print by document, the result is right.
It is the half data of A4 data.

I confused with these appearance, and don't know where is the error.
How can I modify this bug?