>So is there a default padding method value>assumed if none is specified for a block cipher?
The test cases show always specifying a padding method for modes that can have padding which is a pretty logical approach.
Absent specification of a padding method the server is free to pick whatever default value it wants - i.e. the specification does not say what you must do under those circumstances. A server could reject the request, or apply whatever padding method it wants too (including a padding method of none).Â
For CBC mode of a cipher you would expect to see padding on by default logically as operating without padding makes little sense as a default - i.e. asking for no padding is the unusual option. Look at various cryptographic APIs and see how they treat things - is padding on by default and turned off if you don't want it (e.g. see OpenSSL handling where it is precisely that - you have to turn padding off explicitly with a call if you don't want to have padding).
So following the test cases, you need to specify what you want to see as the padding mode - leaving it unspecified can (and as you have seen will) result in non-interoperable outcomes.
Tim.