Calling functions from another file

[Larz60+]

You can see what your program will, and will not see, by running this simple script
(from interactive python)
>>> import sys
>>> sys.path

If you don't see the directory where your second program is located, it wont be found.
__init__.py will fill in the gaps.

[snippsat]

my_unitest folder in sys.path,structured as packages.
Use pytest 

my_uintest/
  folder_a/
  |-- __init__.py
  |-- file_a.py
  folder_b/
  |-- __init__.py
  |-- file_b.py

file_a.py:

import unittest

class A(unittest.TestCase):
   def testA(self):
       self.assertEqual(42, 43)

file_b.py:

import unittest
from my_uintest.folder_a import file_a
  
class B(unittest.TestCase):
   def testA(self):
       file_a.A.testA(self)       

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

Test:

Output:
λ python file_b.py
F
======================================================================
FAIL: testA (__main__.B)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "file_b.py", line 6, in testA
    file_a.A.testA(self)
  File "C:\Python36\my_uintest\folder_a\file_a.py", line 5, in testA
    self.assertEqual(42, 43)
AssertionError: 42 != 43

----------------------------------------------------------------------
Ran 1 test in 0.001s

FAILED (failures=1)