用单元测试为Python项目导入模块/软件包的正确方法是什么？

Question

I have the following directory structure:

|_ director_script.py
|_ app/
      |_ __init__.py
      |_ ParentClass.py
      |_ my_module/
                 |_ __init__.py
                 |_ MyClass.py
                 |_ MyClassTestCase.py

In my director_script.py I use MyClass and when I run python director_script.py the scripts run as expected without any error. However, when I cd into my_module folder and run the unit tests using python -m unittest MyClassTestCase , I get the error:

ModuleNotFoundError: No module named 'app'

This caused by the import statement in MyClass.py that is

from app.ParentClass import ParentClass

This import is fine when I run it from director_script.py and only happens with the unit test.

Answer 1

You should run from outside the app folder, any folder that has an __init__.py is a submodule in python. If you set the current working directory to my_module, it cannot see the app module, unless you have the folder path corresponding to the app folder set in the PYTHONPATH environment variable

Answer 2

在顶层文件夹中添加一个名为__init__.py的文件

Answer 3

A bit of a kludge, but this is how I usually do it:

import sys
sys.path.append('../app')

Or under Windows:

sys.path.append('..\\app')

This needs to come before your module import, of course.