Reference files loaded on a GIT repo can only be on the root directory master branch #54

Among the options to specify the location of reference files for testing, one can give a GIT repository, see, e.g., the settings for ScalableTestSuite. Unfortunately, it seems that the only option as of today is that the files must on the master branch. If the repo has a main branch (which is the default on GitHub), the test.py script fails at line 356.

We should give an option to specify both the branch name and possibily a subdirectory name to locate the reference files for our CI.