(DRAFT / in-progress) cover remaining un-covered code

[ilaflott]

edit: wait/hold in light of #208

This will be a big issue on current uncovered lines, summarizing the kind of tests i think fremor still needs, what lines those tests address, and how urgent it is to implement. some of the currently-uncovered lines are more important than others.

to-be-filled in based on codecov and my notes:

• fremor/cmor_config.py one uncovered line

  • LXYZ,

• fremor/cmor_yamler.py one uncovered line

  • LXYZ,

• fremor/cmor_helpers.py 2-3 dozen uncovered lines

  • lines LABC - LXYZ,
  • lines LABC - LXYZ,
  • lines LABC - LXYZ,
  • lines LABC - LXYZ,
  • ... more?

• fremor/cmor_mixer.py 5-6 dozen uncovered lines

  • lines LABC - LXYZ,
  • lines LABC - LXYZ,
  • lines LABC - LXYZ,
  • lines LABC - LXYZ,
  • ... more?