How to test container class?
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I have a class ListContainer.
The class a container for a list and allow 3 operations:
1. add . 2. remove . 3. getNotValid (return list of not valid elements).

The list is private in the class, so i cannot check that add really add element.
How do you think I should test the add functionality.

for my opinion I should check it by the getnotvalid.

Thank you