Python imports can get weird, specially when dealing with tests that are to be kept separate from the application code (i.e., in sibling directories).

This is a quick guide on how you can organize your tests with pytest so that everything works as expected. If pytest is new for you, check out their docs. PyTest is a framework for writing small, readable tests for python programs.

I’ve kept this article as a note to myself and friends, and now I am publishing it online. It is made to be brief, with minimal explanations, because it shows you an example of how to do something pretty simple.

Do note that while this is not the only way to make things work, it’s my favorite out of everything I’ve come across before.

Organizing pytest tests

The code

Your code should be organized in packages, and the directory with all the tests should be right next to the package directories.

This might sound counterintuitive because the test code from the tests directory should not be able to reach your package, since it is not in a child directory. The reason this works, in a nutshell, is that pytest operates on a broader scope.

Directory structure

pkg/
  code.py
tests/
  __init__.py
  test_code.py

File structure

As for your files, you can basically use imports as you would feel the most comfortable doing: from each package you can import a module, or something from this module.

The tests package needs an __init__ file.

# pkg/code.py
def f(x):
    return x+2

# tests/__init__.py
# (may be left empty)

# tests/test_code.py
from pkg.code import f


def test_f():
    assert f(2) == 4

The testing

Now you can run your tests with the pytest command. That’s it! 😊