pytest-datadir

pytest plugin for manipulating test data directories and files.

Usage

pytest-datadir automatically looks for a directory matching your module's name or a global data folder.

Consider the following directory structure:

.
├── data/
│   └── hello.txt
├── test_hello/
│   └── spam.txt
└── test_hello.py

You can access file contents using the injected fixtures:

• datadir (for module-specific test_* folders)
• shared_datadir (for the global data folder)

def test_read_global(shared_datadir):
    contents = (shared_datadir / "hello.txt").read_text()
    assert contents == "Hello World!\n"


def test_read_module(datadir):
    contents = (datadir / "spam.txt").read_text()
    assert contents == "eggs\n"

The contents of the data directory are copied to a temporary folder, ensuring safe file modifications without affecting other tests or original files.

Both datadir and shared_datadir fixtures return pathlib.Path objects.

lazy_datadir

Version 1.7.0 introduced the lazy_datadir fixture, which only copies files and directories when accessed via the joinpath method or the / operator.

def test_read_module(lazy_datadir):
    contents = (lazy_datadir / "spam.txt").read_text()
    assert contents == "eggs\n"

Unlike datadir, lazy_datadir is an object that only implements joinpath and / operations. While not fully backward-compatible with datadir, most tests can switch to lazy_datadir without modifications.

License

MIT.