Assignment #3 (Testing): README has unnecessary instruction

[Rita-Centeno]

In the 3rd step of section "2- Fixtures" of the 3rd Assignment, it says to "modify your main function so that the cleaned DataFrame is always returned. That will allow you to compare it with the expected fixture".
As we will be testing each function (load_data, clean_data and save_data) individually, it does not make sense to be testing the main function as well. This means that there is no point in making main return the cleaned dataframe (the cleaned dataframe is already returned by the cleaned_data function).

[MrCordeiro]

If you’re not testing the main function—especially if it’s public—you’re leaving a door open for potential issues. Inner functions could be swapped out, bugs could slip in, and you might not catch them.

Testing the main function acts as an integration test. It’s an important step and shouldn’t be skipped.