ID3v2 FrameID + Tests suite

[nerochiaro]

Hi,
I have a question about the method frameID from ID3v2::Frame.
Why does it return a ByteVector ?
Unless i'm reading the ID3v2 standard incorrectly the frame ID is 4
characters long and each character can be any of "capital A-Z and
0-9".
And with "character" the standard seems to really mean "byte".

So, is there a reason for not using just a Latin-1-encoded
TagLib::String there ?
Just curious.

Also, since i'm posting, i'll throw in another question.
Is there any test suite available to exercise the full TagLib API ?

I can see only a file with some tests for some toolkit classes in the
tests directory in 1.4 release, but basically nothing to test the
tagging-specific functionality, especially the more messy aspects like
ID3v2 frames.
I ask this because in the ruby bindings I wrapped basically all of
TagLib's functionality.
I just need to test that everything was done correctly before releasing them.
Having a good test suite that I can take as a base to check that
everything is ok would really help.

Thanks.