Python - organising code and test suite

Question

I am very new to python, coming from a php background and cant figure out the best way to organise my code.

Currently I am working through the project euler exercises to learn python. I would like to have a directory for my solution to the problem and a directory that mirrors this for tests.

So ideally:

Problem
    App
        main.py
    Tests
        maintTest.py

Using php this is very easy as i can just require_once the correct file, or amend the include_path.

How can this be achieved in python? Obviously this is a very simplistic example - therefore some advice on how this is approached on a larger scale would also be extremely grateful.

See related question http://stackoverflow.com/questions/1849311/how-should-i-organize-python-source-code — Mihai8, Jun 22 '13 at 10:16

User · Accepted Answer · 2013-06-22T09:47:44.880

0

This depends on which test runner you want to use.

pytest

I recently learned to like pytest.

It has a section about how to organize the code.

If you can not import your main into the code then you can use the tricks below.

unittest

When I use unittest I do it like this:

with import main

Problem
    App
        main.py
    Tests
        test_main.py

test_main.py

import sys
import os
import unittest
sys.path.append(os.path.join(os.path.dirname(__file__), 'App'))
import main

# do the tests

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

or with import App.main

Problem
    App
        __init__.py
        main.py
    Tests
        test.py
        test_main.py

test.py

import sys
import os
import unittest
sys.path.append(os.path.dirname(__file__))

test_main.py

from test import *
import App.main

# do the tests

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

edited Jun 22 '13 at 09:47

answered Jun 22 '13 at 09:33

User

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What is __init__.py useful for in this example? – Marty Wallace Jun 22 '13 at 09:39
`__init__.py` is an empty file that makes App a package. This makes `import App` import `App/__init__.py` and you can import `App/main` with `import App.main` – User Jun 22 '13 at 09:40
So python sees any __init__.py files and adds that location to the path? – Marty Wallace Jun 22 '13 at 09:42
No. When you do `import App` Python looks in every directory in `sys.path` for something with the name `App`. If App is a file, it is imported. If App is a directory and has a `__init__.py` then the `__init__.py` is taken. – User Jun 22 '13 at 09:45
AttributeError: 'module' object has no attribute 'dirname' – Marty Wallace Jun 22 '13 at 09:57
fixed that.. it should be os os.path.dirname i guess. – User Jun 22 '13 at 10:23

score 0 · Answer 2 · edited Jun 20 '20 at 09:12

I have always loved nosetests, so here is my solution:

Problem

App

    __init__.py
    main.py

Tests

    __init__.py
    tests.py

Then, open the command prompt, CD to /path/to/Problem and type:

nosetests Tests

it will automatically recognize and run the tests. However, read this:

Any python source file, directory or package that matches the testMatch regular expression (by default: (?:^|[b_.-])[Tt]est) will be collected as a test (or source for collection of tests). [...]

Within a test directory or package, any python source file matching testMatch will be examined for test cases. Within a test module, functions and classes whose names match testMatch and TestCase subclasses with any name will be loaded and executed as tests.

This basically means that your tests (both your files and function/methods/classes) have to begin with the "test" or "Test" word.

More on Nosetests usage here: Basic Usage.

Python - organising code and test suite

2 Answers2