unit test of function in different directory gives AttributeError: module has no attribute

What specific syntax must be changed below in order for a unit test running in one part of a file system to successfully test a function in a class that is located in a completely different part of a file system?

The test file is located at C:pathtosome-test-classestest_an_example.py

The class being tested is located at C:\completely\different\path\an_example.py

The problem might be in the structure of C:\completely\different\path\an_example.py, because the C:\completely\different\path\an_example.py IS being imported into C:pathtosome-test-classestest_an_example.py as shown below.

Here are the details:

TEST FILE:

The test file located at C:pathtosome-test-classestest_an_example.py is:

import unittest
import subprocess

#Run the tests in this file by running the following command in the terminal:
#python -m unittest test_an_example.py

class TestCommandBuilder(unittest.TestCase):

  def test_someMethod(self):
    import sys
    sys.path.insert(0, 'C:\completely\different\path\')
    print('sys.path is: ', str(sys.path))
    import an_example
    print('90909090')
    firstString = "hello"
    secondString = ' there'
    returnBool = an_example.someMethod(firstString, secondString)
    self.assertTrue(returnBool)

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

CLASS BEING TESTED:

The class being tested is located at C:\completely\different\path\an_example.py and contains the following:

class an_example:

  def __init__(self):  
    pass

  def someMethod(firstString, secondString):
    print("^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^")
    print("firstString is: ",firstString)
    print("secondString is: ",secondString)
    combinedString = firstString+secondString
    print("^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^")
    if combinedString == "hello there":
      return True
    else: 
      return False

CURRENT ERROR:

Currently, the following error is being returned:

C:pathtosome-test-classes>python -m unittest test_an_example.py
sys.path is:  ['C:\completely\different\path\', 'C:\path\to\some-test-classes', 'C:\Users\user\AppData\Local\Programs\Python\Python310\python310.zip', 'C:\Users\user\AppData\Local\Programs\Python\Python310\DLLs', 'C:\Users\user\AppData\Local\Programs\Python\Python310\lib', 'C:\Users\user\AppData\Local\Programs\Python\Python310', 'C:\Users\user\AppData\Local\Programs\Python\Python310\lib\site-packages']
90909090
E
 ======================================================================  
ERROR: test_someMethod (test_an_example.TestCommandBuilder)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:pathtosome-test-classestest_an_example.py", line 62, in test_someMethod
    returnBool = an_example.someMethod(firstString, secondString)
AttributeError: module 'an_example' has no attribute 'someMethod'

----------------------------------------------------------------------
Ran 1 test in 0.006s

FAILED (errors=1)

As you can see from the results of the print(...) commands in the above, the class an_example IS being loaded into test_an_example.py, but the someMethod(firstString, secondString) member of the an_example class is NOT being found.

Answer

Your code works fine. The issue is that you never import the an_example class. In your test file you import an_example but you are importing the module. You can actually see it in the traceback:

AttributeError: module ‘an_example’ has no attribute ‘someMethod’

In order to import the class an_example you would need to do something like this:

  def test_someMethod(self):
    import sys
    sys.path.insert(0, 'C:\completely\different\path\')
    print('sys.path is: ', str(sys.path))

    # import an_example  # remove this

    from an_example import an_example        # changed this

    print('90909090')
    firstString = "hello"
    secondString = ' there'
    returnBool = an_example.someMethod(firstString, secondString)
    self.assertTrue(returnBool)

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Answer