Apply best practices to testing

[ecsim]

Apply best practices to testing

[sepandhaghighi]

Hi @nnadeau

I used doctest.testfile method because of .coverage file merge problem in docstring mode, and we have some output style test in OPEM that I think doctest is better than pytest and unittest in this case.

Thanks

[engnadeau]

Can you please provide a more detailed description of the merge problem and output style test?

[sepandhaghighi]

@nnadeau

Merge problem : each function tests in docstring mode create one .coverage file and this file overwrite by next.

Output style test : some functions output style in console

Thanks