Fixing bug #120

[jbscoggi]

This fixes bug #120 which should have occurred whenever pure species collision integrals were requested in mppequil with a mixture that does not have electrons. A new test is also added to ensure the bug is caught in the future if it is mistakenly added back.

[codecov[bot]]

Codecov Report

Merging #122 into master will decrease coverage by 3.12%. The diff coverage is 75.00%.

@@            Coverage Diff             @@
##           master     #122      +/-   ##
==========================================
- Coverage   73.20%   70.07%   -3.13%     
==========================================
  Files         133      134       +1     
  Lines        7863     8451     +588     
==========================================
+ Hits         5756     5922     +166     
- Misses       2107     2529     +422     

Impacted Files	Coverage Δ
src/general/mppequil.cpp	27.79% <75.00%> (ø)
src/transport/Transport.h	70.00% <0.00%> (-30.00%)	:arrow_down:
src/thermo/Thermodynamics.h	75.00% <0.00%> (-6.82%)	:arrow_down:
src/transport/CollisionDB.h	97.61% <0.00%> (+0.05%)	:arrow_up:
src/thermo/Thermodynamics.cpp	37.26% <0.00%> (+0.42%)	:arrow_up:
src/thermo/StateModel.h	71.83% <0.00%> (+1.40%)	:arrow_up:
src/utilities/StringUtils.cpp	78.84% <0.00%> (+5.76%)	:arrow_up:

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 3f9a791...ad49367. Read the comment docs.

[jbscoggi]

Not seeing any reason the testing coverage should have decreased and the report seems to be a little fishy. I think this might be a side effect from the coverage not working for a little while in the last months. Clearly, the changes are minimal and I don't expect this PR to negatively affect the code base.