Update emissions.py with CO2 equivalent notation

[byersiiasa]

Added CO2-eq notation as this is currently used in our AR6 and other variable templates

[khaeru]

I suspect this may not work, because the underlying package, pint, interprets "-" as a minus sign. But let's see.

[codecov-commenter]

Codecov Report

Merging #36 (9245808) into main (00857b7) will not change coverage. The diff coverage is 0.00%.

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@@           Coverage Diff           @@
##             main      #36   +/-   ##
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  Coverage   73.10%   73.10%           
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  Files           4        4           
  Lines         145      145           
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  Hits          106      106           
  Misses         39       39           

Impacted Files	Coverage Δ
iam_units/emissions.py	100.00% <ø> (ø)
iam_units/update.py	0.00% <0.00%> (ø)

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[danielhuppmann]

Note that you edited a file that has as its first line "# DO NOT ALTER THIS FILE MANUALLY!"...

[khaeru]

@danielhuppmann good eye! 😅

@byersiiasa you should instead modify the variable _EMI_EQUIV in the file update.py.

[byersiiasa]

Please expand the tests so that the new symbol you've added is tested:

https://github.com/IAMconsortium/units/blob/00857b7e1e1737726ea59e0679ba1c300e2d612e/iam_units/test_all.py#L86-L103

@khaeru sorry not quite intuitive to me here, should I add: (None, "CO2-eq", "CO2e", 1.0) or other like (None, "CO2", "CO2-eq", 1.0)

Also - #L92 ("AR5GWP100", "CH4", "CO2e", 28), should not have the e? or should all L89-94 be CO2e?

[khaeru]

Here are the relevant pytest docs: https://docs.pytest.org/en/stable/how-to/parametrize.html

To paraphrase, the 4 elements of that tuple get mapped to the function arguments named on L87, i.e. "species_in", "species_out", etc. Then you can see in the function body how those are used to call the tested function. Each line is an individual test case, so e.g.

• ("AR5GWP100", "CH4", "CO2", 28), tests that this particular conversion works,
• ("AR5GWP100", "CH4", "CO2e", 28), tests that "CO2e" is recognized as equivalent to "CO2" for a target ("species_out"), etc.

You could test "CO2-eq" as species_in and/or species_out, depending on how you expect that it should work!