restrict test_cases_in_separate_dirs to the base set of FS test cases (since we know these are relatively quick to run)
restrict test_cases_in_separate_dirs to the base set of FS test cases (since we know these are relatively quick to run)

zopyx/pyfilesystem,pombreda/pyfilesystem,Konubinix/pyfilesystem,piranna/pyfilesystem,PyFilesystem/pyfilesystem,pmitros/pyfs,pmitros/pyfs,rivenz/pyfilesystem,flying-circus/pyfilesystem