Feature multiple loudness metadata squash tests

[rsjbailey]

fixes #84

Use generic parameter tests
Add a generic test for vector parameters
Allow a custom comparator for vector parameters (defaults to using operator==)
Fix missing unset(ContentKind) implementation

[codecov-commenter]

Codecov Report

Merging #110 (4e13581) into 2076-2 (bba67f8) will decrease coverage by 0.43%.
The diff coverage is 82.69%.

@@            Coverage Diff             @@
##           2076-2     #110      +/-   ##
==========================================
- Coverage   90.78%   90.35%   -0.44%     
==========================================
  Files         122      120       -2     
  Lines        5700     5557     -143     
==========================================
- Hits         5175     5021     -154     
- Misses        525      536      +11     

Impacted Files	Coverage Δ
...clude/adm/elements/audio_block_format_binaural.hpp	93.75% <ø> (-0.37%)	⬇️
...dm/elements/audio_block_format_direct_speakers.hpp	100.00% <ø> (ø)
include/adm/elements/audio_block_format_hoa.hpp	100.00% <ø> (ø)
include/adm/elements/audio_block_format_id.hpp	100.00% <ø> (ø)
include/adm/elements/audio_block_format_matrix.hpp	93.75% <ø> (-0.37%)	⬇️
...nclude/adm/elements/audio_block_format_objects.hpp	100.00% <ø> (ø)
include/adm/elements/audio_channel_format.hpp	94.64% <ø> (-0.10%)	⬇️
include/adm/elements/audio_channel_format_id.hpp	100.00% <ø> (ø)
include/adm/elements/audio_content_id.hpp	100.00% <ø> (ø)
include/adm/elements/audio_object.hpp	100.00% <ø> (ø)
... and 124 more

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[tomjnixon]

If add finds a duplicate, should it replace it rather than just returning false? If the comparator checks the full value (like operator==) then the current behaviour makes sense, but if it just checks a key (like a language for example) then the new value should replace the old one.

[rsjbailey]

If add finds a duplicate, should it replace it rather than just returning false? If the comparator checks the full value (like operator==) then the current behaviour makes sense, but if it just checks a key (like a language for example) then the new value should replace the old one.

That makes sense, but add() then becomes a bit of a misleading name. I guess the stl equivalent would be insert_or_assign, although it's not especially catchy.

[tomjnixon]

Yeah, good point. Another alternative would be to use set/unset for things like this which are expected to be unique.

As long as it's documented it's probably OK.