[Tutor] Using Class Properly - early beginner question

[boB Stepp]

On Fri, Mar 24, 2017 at 6:51 AM, Rafael Knuth <rafael.knuth at gmail.com> wrote:
> Thank you so much for your help.
> I have a question: When creating an instance of GroceryListMaker, you are using:
>
> if __name__ == "__main__":
>
> What is that specifically for?
> I tested your code and both worked, with and without
> if __name__ == "__main__":
>
> a)
>
> if __name__ == "__main__":
>     my_shopping_list = GroceryListMaker()
>     my_shopping_list.make_shopping_list()
>     my_shopping_list.display_shopping_list()
>
> b)
>
> my_shopping_list = GroceryListMaker()
> my_shopping_list.make_shopping_list()
> my_shopping_list.display_shopping_list()
>
> Can you explain?

Alan in his post pretty much said it all.  I do this to cover files
that I may want to reuse, that is, import classes, functions, etc.
from them in future programs without running the initializer code
after the if statement.  The main reason that I am doing this
construction almost all of the time now, however, is that I have been
striving to write unit tests for my code.  When I run a test suite I
don't want the "if __name__ ..." code to run in the files I am
testing.  However, in one of my unit test files I will similarly have:

if __name__ == '__main__':
    unittest.main()

which will run the tests when the test file is run directly.

See https://docs.python.org/3/library/unittest.html for the Python 3
docs on the unittest module.