I was surprised that in the following __init__ is actually called once per test function, although nothing in documentation implied so.

a.py
------

import unittest

class A(unittest.TestCase):
   def __init__(self, *args, **kwargs):
       print('called only once!')
       super().__init__(*args, **kwargs)

   def test(self):
       self.assertEqual(1, 1)
 
   def test2(self):
       self.assertEqual(2, 2)

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

$ python a.py
called only once!
called only once!
..
----------------------------------------------------------------------
Ran 2 tests in 0.001s

OK



The attached patch adds a note regarding this behaviour for the TestCase class.