Encode tests

[gauntl3t12]

Increase test coverage of the encode module.

Hard code the time string created by the json encoder for tests

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 64.88%. Comparing base (f688e38) to head (6dcf08c).

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Additional details and impacted files

@@            Coverage Diff             @@
##             main     #359      +/-   ##
==========================================
+ Coverage   63.42%   64.88%   +1.46%     
==========================================
  Files          25       25              
  Lines        1572     1572              
==========================================
+ Hits          997     1020      +23     
+ Misses        575      552      -23     

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[gauntl3t12]

Now that once_cell is being pulled into the standard library in 1.70, we can bump to that and utilize the new standardized interface. Or, I can make similar modifications to the once_cell version to allow for dependency injection. @estk I'll defer to you on that decision. I know 1.70 is only 8 months old.

[estk]

Ya lets stick to 1.69 for now

[gauntl3t12]

@estk Swapped to OnceCell instead. I kept the version using the standard library in a separate branch that I'll submit towards the middle of the year when we look at moving up.