Refactoring and test coverage

[jstucke]

• fixed naming collision in test
• added flake8 config file
• added flake8 github action

[codecov-io]

Codecov Report

Merging #522 (797cf12) into master (d768e7d) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #522   +/-   ##
=======================================
  Coverage   95.61%   95.61%           
=======================================
  Files         302      302           
  Lines       18193    18193           
=======================================
  Hits        17395    17395           
  Misses        798      798           

Impacted Files	Coverage Δ
...ion/scheduler/test_regression_virtual_file_path.py	98.64% <100.00%> (ø)

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[github-actions]

Lintly has detected code quality issues in this pull request.