fix: skip determination of boundary types when no boundary rxns exist

[ChristianLieven]

Fixes #732

[cdiener]

Nice catch. The original error you reported was in the heuristic to identify the external compartment, so that probably needs a fix as well...

[ChristianLieven]

@cdiener Am I not sufficiently circumventing that heuristic by skipping find_external_compartment altogether with the check I've implemented in find_boundary_types? As far as I can tell that is the only place in the code where find_external_compartment is called. It uses boundary reactions to identify the external compartment, so not running it at all when there are no boundary reactions seemed like an elegant solution to me as opposed to handling the error there and then having to refactor all depending functions. I guess this is a conceptual question so I'm happy to follow whatever you feel is more sensible! :)

[codecov-io]

Codecov Report

Merging #733 into devel will decrease coverage by <.01%.
The diff coverage is 80%.

@@            Coverage Diff             @@
##            devel     #733      +/-   ##
==========================================
- Coverage   82.98%   82.98%   -0.01%     
==========================================
  Files          40       40              
  Lines        3867     3872       +5     
  Branches      882      883       +1     
==========================================
+ Hits         3209     3213       +4     
- Misses        458      459       +1     
  Partials      200      200

Impacted Files	Coverage Δ
cobra/medium/boundary_types.py	88.88% <80%> (-1.44%)	⬇️

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[cdiener]

I agree that it fixes the bug but find_boundary_compartment is still a public function in that API, so it should also throw an error if there are no boundary reactions since there might be someone using that function on its own.

[cdiener]

Nice, thanks!

[ChristianLieven]

Oops saw that there was a mistyped bit of plaintext in my code. :S Removed that in the latest commit.