The tmp_path fixture
You can use the tmp_path fixture which will provide a temporary
directory unique to the test invocation, created in the [base temporary
directory](#base temporary directory).
tmp_path is a pathlib.Path object. Here is an example test usage:
# content of test_tmp_path.py
CONTENT = "content"
def test_create_file(tmp_path):
d = tmp_path / "sub"
d.mkdir()
p = d / "hello.txt"
p.write_text(CONTENT)
assert 0
Running this would result in a passed test except for the last
assert 0 line which we use to look at values:
$ pytest test_tmp_path.py
platform linux -- Python 3.x.y, pytest-6.x.y, py-1.x.y, pluggy-0.x.y
cachedir: $PYTHON_PREFIX/.pytest_cache
rootdir: $REGENDOC_TMPDIR
collected 1 item
test_tmp_path.py F [100%]
_____________________________ test_create_file _____________________________
tmp_path = PosixPath('PYTEST_TMPDIR/test_create_file0')
def test_create_file(tmp_path):
d = tmp_path / "sub"
d.mkdir()
p = d / "hello.txt"
p.write_text(CONTENT)
> assert 0
E assert 0
test_tmp_path.py:13: AssertionError
FAILED test_tmp_path.py::test_create_file - assert 0
The tmp_path_factory fixture {#tmp_path_factory example}
The tmp_path_factory is a session-scoped fixture which can be used to
create arbitrary temporary directories from any other fixture or test.
It is intended to replace tmpdir_factory, and returns
pathlib.Path{.interpreted-text role=“class”} instances.
See
tmp_path_factory API <tmp_path_factory factory api>{.interpreted-text
role=“ref”} for details.
The 'tmpdir' fixture
You can use the tmpdir fixture which will provide a temporary
directory unique to the test invocation, created in the [base temporary
directory](#base temporary directory).
tmpdir is a
py.path.local object
which offers os.path methods and more. Here is an example test usage:
# content of test_tmpdir.py
def test_create_file(tmpdir):
p = tmpdir.mkdir("sub").join("hello.txt")
p.write("content")
assert 0
Running this would result in a passed test except for the last
assert 0 line which we use to look at values:
$ pytest test_tmpdir.py
platform linux -- Python 3.x.y, pytest-6.x.y, py-1.x.y, pluggy-0.x.y
cachedir: $PYTHON_PREFIX/.pytest_cache
rootdir: $REGENDOC_TMPDIR
collected 1 item
test_tmpdir.py F [100%]
_____________________________ test_create_file _____________________________
tmpdir = local('PYTEST_TMPDIR/test_create_file0')
def test_create_file(tmpdir):
p = tmpdir.mkdir("sub").join("hello.txt")
p.write("content")
> assert 0
E assert 0
test_tmpdir.py:9: AssertionError
FAILED test_tmpdir.py::test_create_file - assert 0
The 'tmpdir_factory' fixture {#tmpdir factory example}
The tmpdir_factory is a session-scoped fixture which can be used to
create arbitrary temporary directories from any other fixture or test.
For example, suppose your test suite needs a large image on disk, which
is generated procedurally. Instead of computing the same image for each
test that uses it into its own tmpdir, you can generate it once
per-session to save time:
# contents of conftest.py
import pytest
@pytest.fixture(scope="session")
def image_file(tmpdir_factory):
img = compute_expensive_image()
fn = tmpdir_factory.mktemp("data").join("img.png")
img.save(str(fn))
return fn
# contents of test_image.py
def test_histogram(image_file):
img = load_image(image_file)
# compute and test histogram
See tmpdir_factory API <tmpdir factory api>{.interpreted-text
role=“ref”} for details.
The default base temporary directory {#base temporary directory}
Temporary directories are by default created as sub-directories of the
system temporary directory. The base name will be pytest-NUM where
NUM will be incremented with each test run. Moreover, entries older
than 3 temporary directories will be removed.
You can override the default temporary directory setting like this:
pytest --basetemp=mydir
::: {.warning}
::: {.title}
Warning
:::
The contents of mydir will be completely removed, so make sure to use
a directory for that purpose only.
:::
When distributing tests on the local machine using pytest-xdist, care
is taken to automatically configure a basetemp directory for the sub
processes such that all temporary data lands below a single per-test run
basetemp directory.