Refactored and added cnetstats tests (#3702)

* Abstracted cnetstats.

* Added default test for cnetstats and cleaned up imports.

* Added more tests.

* Added exception tests.

* Removed unnecessary tests.

* Removed old makefiles.

* Added docstrings and renamed test.

* Added temp dir for test files (#3692)

* Added temp dir for test files

* Moved to fixture inheritance

* Added valid check

* Updated tests to use new fixtures

* Fixed build errors

* Fixed build warning

* Updated winnow test

* updated tests to pass

Co-authored-by: Jesse Mapel <jam826@nau.edu>
Co-authored-by: Kelvin Rodriguez <kr788@nau.edu>