pytest cannot find module [duplicate]

Answer 1

Simply add __init__.py to the tests directory, and to all directories recursively inside it that contain test files.

Answer 2

Just put an empty conftest.py file in the project root directory:

$ pwd
/home/usr/tmp/junk
$ touch conftest.py

Your project structure should become:

junk
├── conftest.py
├── junk
│   ├── __init__.py
│   └── ook.py
└── tests
    └── test_ook.py

What happens here: when pytest discovers a conftest.py, it modifies sys.path so it can import stuff from the conftest module. So, since now an empty conftest.py is found in rootdir, pytest will be forced to append it to sys.path. The side effect of this is that your junk module becomes importable.