Nearly all of them are "device-independent," in the sense that the
actual device characteristics don't matter. They do all require a color
device, though; and one or two require a 96dpi device.
Of course, not everything in the specification can be tested that way.
In particular the tests don't check that the UA reports the true device
characteristics. And some other statements in the specification, such
as "A ‘resolution’ query never matches a device with non-square
pixels," cannot be tested either without an actual device with
non-square pixels...
Opera 9.64 (under Debian Linux 5.0 "Lenny") passes most tests but fails
on the following:
It seems Opera's bug is treating invalid queries as false instead of
ignoring them. E.g., '(min-width: -1px)' is true in Opera but should be
ignored according to the specification.
Of course, there may be errors in the tests as well...