Remove pytest-openfiles, fix unit string comparison in doctests - #350

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Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (6c2bd36) 97.09% compared to head (e50ef21) 97.09%.

@@           Coverage Diff           @@
##           master     #350   +/-   ##
=======================================
  Coverage   97.09%   97.09%           
=======================================
  Files          17       17           
  Lines        2030     2032    +2     
=======================================
+ Hits         1971     1973    +2     
  Misses         59       59           

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