change: Add tests for complicated observables for OQ3, shots > 0

[kshyatt-aws]

Issue #, if available: N/A

Description of changes:

• Get coverage >98%
• Refactor simulate to be more modular and easier to read
• Add docstrings
• Add parsing for duration, barrier, reset, stretch so that users can submit QASM scripts with them but are warned that (for now) they are no-ops

Testing done:
Unit tests passed locally

Merge Checklist

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• I have read the CONTRIBUTING doc
• I used the commit message format described in CONTRIBUTING
• I have updated any necessary documentation, including READMEs and API docs (if appropriate)

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• I have added tests that prove my fix is effective or that my feature works (if appropriate)
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[codecov]

Codecov Report

Attention: Patch coverage is 98.23529% with 3 lines in your changes missing coverage. Please review.

Project coverage is 98.87%. Comparing base (89be354) to head (5b69045).
Report is 1 commits behind head on main.

Files	Patch %	Lines
src/Quasar.jl	94.23%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #39      +/-   ##
==========================================
+ Coverage   97.63%   98.87%   +1.23%     
==========================================
  Files          23       23              
  Lines        3174     3194      +20     
==========================================
+ Hits         3099     3158      +59     
+ Misses         75       36      -39     

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[rmshaffer]

Noted a few places where there is commented-out code that should probably be dealt with before merging.

Also as a meta-comment, it seems like there is a lot of linting/code restructuring in this PR which is not (necessarily) related to the functional part of the PR (adding tests for code coverage) - for reviewer sanity in the future it would be great to keep functional changes separate from non-functional changes as much as possible. Otherwise it's not easy to tell what code is "new" vs. "moved", and so hard to know where to focus attention.

[kshyatt-aws]

for reviewer sanity in the future it would be great to keep functional changes separate from non-functional changes as much as possible. Otherwise it's not easy to tell what code is "new" vs. "moved", and so hard to know where to focus attention.

100% agreed, sorry about this. In the future I'll try to split things up, it's just difficult when we are waiting on another feature branch to merge.