With qtype_ddmatch installed, the unit tests for qformat_blackboard_six
fail as they generate ddmatch questions instead of match ones. This
patch checks for ddmatch and changes the test to expect that instead if
its installed.
This works on the expectation that the returned array from readdata()
is opaque and will be fed directly into readquestions() since
filebase is different per file and needs to be set up appropriately
before each parse.
Jean-Michel Vedrine