Use exclusion list to disable select tests from direct mode testing

[mih]

ATM we test a little bit of code for compliance with direct mode, using hand-picked tests. IMHO this should change. There is quite a chunk of usable functionality in direct mode, but from the test perspective it doesn't look like it. I think we should switch to a negative list, disabling only test that fail (possibly for a known reason). The current approach will or will not allow for the status quo to get worse -- we just won't know -- hence it isn't suitable for making progress towards direct mode compatibility.

[bpoldrack]

I agree. Additionally the same is true for v6.

[bpoldrack]

This is a bit more of an effort than I expected it to be.
Apparently nose can't easily exclude a list of tests out of the box, but only entire files/directories or via regexes.
Current approach: Have a "dry-run" of nose to discover all tests (sadly by name), do a lot of grep'ing and sed'ing to get a unique list of tests adressed via /path/to/file.py:test, build difference to exclusion list and build a nose.cfg from the result to run those tests only.
The exclusion list itself (actually there are two - DM and V6) is build similarly but in an one time effort and is supposed to be maintained manually.