Python unittest在运行时发现

Question

I'm trying to run my unit tests for a python module from a separate test script. Here is my file structure

- root
  |- modules
     |- a_module.py
  |- test
     |- test_a_module.py
  |- main.py

The main.py looks like this:

import unittest

loader = unittest.TestLoader()
suite = loader.discover(start_dir='./test', pattern='test_*.py')

runner = unittest.TextTestRunner()
runner.run(suite)

And here are a_module.py and test_a_module.py :

# a_module.py
def something():
    return True

# test_a_module.py
import unittest

from ..modules.a_module import something

class TestSomething(unittest.TestCase):
    def test_something(self):
        self.assertTrue(something)

When running python3 main.py I get the following error.

======================================================================
ERROR: test_a_module (unittest.loader._FailedTest)
----------------------------------------------------------------------
ImportError: Failed to import test module: test_a_module
Traceback (most recent call last):
  File "/usr/lib/python3.7/unittest/loader.py", line 436, in _find_test_path
    module = self._get_module_from_name(name)
  File "/usr/lib/python3.7/unittest/loader.py", line 377, in _get_module_from_name
    __import__(name)
  File "/home/schu_max/root/test/test_a_module.py", line 3, in <module>
    from ..modules.a_module import something
ImportError: attempted relative import with no known parent package


----------------------------------------------------------------------

I'm relatively new to python and don't have a clue on how to solve this issue. And other questions/answers on SO weren't that helpful either. So how can I get this to work?

Answer 1

There are several ways to make your tests run. Now that they are import packages try

python -m unittest -v in the root package folder, after removing the two dots from the relative import path in test/test_a_module.py . Will work too with python main.py from the same folder. If you issue python -m unittest -v outside root and you prefix the relative path with root it will work too. There are probably other ways.

Just beaware that the relative import paths in the test files are affected by the folder from where you run your test script.

To stay coherent, run your tests always from the same place, and put all your tests inside test/ where you can refer all you root subpackages by relative path, without the need to mention the `root* package name, which is nice because you might want to rename it in the future.