Update for pytest 7 and newer: use the pythonpath setting
Recently, pytest has added a new core plugin that supports sys.path modifications via the pythonpath configuration value. The solution is thus much simpler now and doesn’t require any workarounds anymore:
pyproject.toml example:
[tool.pytest.ini_options]
pythonpath = [
"."
]
pytest.ini example:
[pytest]
pythonpath = .
The path entries are calculated relative to the rootdir, thus . adds junk directory to sys.path in this case.
Multiple path entries are also allowed: for a layout
junk/
├── src/
| └── lib.py
├── junk/
│ ├── __init__.py
│ └── ook.py
└── tests
├── test_app.py
└── test_lib.py
the configuration
[tool.pytest.ini_options]
pythonpath = [
".", "src",
]
or
[pytest]
pythonpath = . src
will add both lib module and junk package to sys.path, so
import junk
import lib
will both work.
Original answer
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.