Add CLI help tests

[ColeFrench]

I'm adding some CLI tests in preparation for maybe implementing some of the suggestions in #1070.

Drafting this PR to check CI checks. Code may be wrong in the meantime.

[codecov[bot]]

Codecov Report

Merging #1069 (4732813) into master (7931a85) will decrease coverage by 0.43%. The diff coverage is n/a.

:exclamation: Current head 4732813 differs from pull request most recent head 8e59005. Consider uploading reports for the commit 8e59005 to get more accurate results

@@            Coverage Diff             @@
##           master    #1069      +/-   ##
==========================================
- Coverage   46.27%   45.85%   -0.43%     
==========================================
  Files         171      171              
  Lines       65139    64180     -959     
==========================================
- Hits        30144    29430     -714     
+ Misses      34995    34750     -245     

see 70 files with indirect coverage changes

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[pkgw]

Hi @ColeFrench — thanks for pursuing on this; more test coverage is always better! I just wanted to inquire about the status here, since this PR hasn't changed for a while. Do you think you might come back to working on it?