Where do the Python unit tests go? [closed]

Question

If you're writing a library, or an app, where do the unit test files go?

It's nice to separate the test files from the main app code, but it's awkward to put them into a "tests" subdirectory inside of the app root directory, because it makes it harder to import the modules that you'll be testing.

Is there a best practice here?

Answer 1

For a file module.py, the unit test should normally be called test_module.py, following Pythonic naming conventions.

There are several commonly accepted places to put test_module.py:

1. In the same directory as module.py.
2. In ../tests/test_module.py (at the same level as the code directory).
3. In tests/test_module.py (one level under the code directory).

I prefer #1 for its simplicity of finding the tests and importing them. Whatever build system you're using can easily be configured to run files starting with test_. Actually, the default unittest pattern used for test discovery is test*.py.

Answer 2

Only 1 test file

If there has only 1 test files, putting it in a top-level directory is recommended:

module/     lib/         __init__.py         module.py     test.py 

Run the test in CLI

python test.py 

Many test files

If has many test files, put it in a tests folder:

module/     lib/         __init__.py         module.py     tests/         test_module.py         test_module_function.py 

# test_module.py  import unittest from lib import module  class TestModule(unittest.TestCase):     def test_module(self):         pass  if __name__ == '__main__':     unittest.main() 

Run the test in CLI

# In top-level /module/ folder python -m tests.test_module python -m tests.test_module_function 

Use unittest discovery

unittest discovery will find all test in package folder.

Create a __init__.py in tests/ folder

module/     lib/         __init__.py         module.py     tests/         __init__.py         test_module.py         test_module_function.py 

Run the test in CLI

# In top-level /module/ folder  # -s, --start-directory (default current directory) # -p, --pattern (default test*.py)  python -m unittest discover 

Reference

• pytest Good Practices for test layout
• unittest

Unit test framework

• nose
• nose2
• pytest