test-pattern: substitute common compression list
The compression list as to be matched with a glob because zstd might not be part
of the option. By using a substitution for these, we won't have to re-glob them
over and over.
# common patterns in test at can safely be replaced
from __future__ import absolute_import
substitutions = [
# list of possible compressions
(br'zstd,zlib,none,bzip2',
br'$USUAL_COMPRESSIONS$'
),
]