Update unit testing

[apulsipher]

Strengthens unit testing:

• Adds tests to test-sir.R to monitor:
  • Model initialization
  • Model output with and without queuing
  • Model run speed with and without queuing
• Adds tests to test-lfmcmc.R to monitor:
  • Model initialization
  • Adding simulation, summary, proposal, kernel functions
  • Using factory proposal and kernel functions
  • Missing/optional parameters
• Created test-sirconn.R, test-sird.R, test-sis.R, test-seir.R with checks for:
  • Model initialization
  • Model runs
  • Model output
• Created test-tool.R with checks for:
  • Tool initialization
  • Tool helpers (print, getters/setters)
  • Adding/removing tools

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 34.37%. Comparing base (e2797fa) to head (2bf7375).
Report is 3 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main      #38       +/-   ##
===========================================
+ Coverage   19.18%   34.37%   +15.18%     
===========================================
  Files          34       36        +2     
  Lines        1777     1882      +105     
===========================================
+ Hits          341      647      +306     
+ Misses       1436     1235      -201     

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[apulsipher]

@gvegayon We should add tests for other files (e.g., other model types, generic model methods, etc), but I think it would be better tackled as separate issues. If you want me to do that here, let me know. Otherwise, I'll create issues for the different areas that need unit testing.

[apulsipher]

@gvegayon I've added a few more test files, but I think this is a good place to stop for this PR. We will add more tests down the line, but we should merge these ones.