Unittest Python - Why Create a Class?

Question

Suppose you are writing unit tests with the unittest framework within Python.

I am used to writing unit tests using classes and various methods for each test e.g. if you had some function cuboid_volume that calculates the volume of a cube:

def cuboid_volume(l):
    return (l*l*l)

Then you would structure units tests as follows:

import unittest

class TestCuboid(unittest.TestCase):
    def test_volume(self):
      self.assertAlmostEqual(cuboid_volume(2),8)
    

However I have also seen examples where unit tests are structured without using a class. Example below:

def test_volume():
  assert cuboid_volume(2) == 8

My question is: what is the benefit of doing this and why use a class in the first place?

Answer 1

benefit to use class

1. you can call inheritted method from class unittest.TestCase, that is why you can use self.assertAlmostEqual
2. group relevant test cases in a class so that they can share common data/properties among relevant test cases. also have same setUp and tearDown called per test method, or setUpClass and tearDownClass per class.