I have a method of a class I'd like to test with pytest, such as the method _method_of_interest below.

class MyClass():
    def __init__(self, stuff):
     ...
    ..
    ..
    def _method_of_interest(self, list1, list2):
        """
        some logic that depends on list1, list2, and self.relevant_info
        Also calls self._helper_method(list)
        """
        output = list1   list2   self._helper_method(list2)   self.relevant_info

  
        return output 

    def _helper_method(self, lista):
        """
        Helper method depends on lista and self.relevant_info
        """
        
        return lista   self.relevant_info

I'd like to be able to test _method_of_interest with different values of list1, list2, and self.relevant_info. So I mostly need to be able to specify a value for self.relevant_info. What is the cleanest way to do this with Python?

CodePudding user response：

The easiest approach would be to use the builtin unittest framework.

Define multiple test cases. In each, you create a new MyClass object with the stuff defined for that test. Then you compare the output of my_class._method_of_interest to some predefined expected output (with the assertEqual method of unittest.TestCase). Of course, you can do multiple test, for multiple different lists 1&2.

EDIT: If you can't set relevant_info through the constructor itself then you can always manually adjust it. Class attributes are not protected in python, no-one can stop you from doing:

my_class = MyClass(unrelevant_info)
my_class.relevant_info = relevant_info

But if you need to do it then there is something fishy going on in the code.