Configuration

Command line options and configuration file settings

You can get help on command line options and values in INI-style configurations files by using the general help option:

pytest -h   # prints options _and_ config file settings

This will display command line and configuration file settings which were registered by installed plugins.

Initialization: determining rootdir and inifile

New in version 2.7.

pytest determines a rootdir for each test run which depends on the command line arguments (specified test files, paths) and on the existence of ini-files. The determined rootdir and ini-file are printed as part of the pytest header during startup.

Here’s a summary what pytest uses rootdir for:

• Construct nodeids during collection; each test is assigned a unique nodeid which is rooted at the rootdir and takes in account full path, class name, function name and parametrization (if any).
• Is used by plugins as a stable location to store project/test run specific information; for example, the internal cache plugin creates a .cache subdirectory in rootdir to store its cross-test run state.

Important to emphasize that rootdir is NOT used to modify sys.path/PYTHONPATH or influence how modules are imported. See pytest import mechanisms and sys.path/PYTHONPATH for more details.

Finding the rootdir

Here is the algorithm which finds the rootdir from args:

• determine the common ancestor directory for the specified args that are recognised as paths that exist in the file system. If no such paths are found, the common ancestor directory is set to the current working directory.
• look for pytest.ini, tox.ini and setup.cfg files in the ancestor directory and upwards. If one is matched, it becomes the ini-file and its directory becomes the rootdir.
• if no ini-file was found, look for setup.py upwards from the common ancestor directory to determine the rootdir.
• if no setup.py was found, look for pytest.ini, tox.ini and setup.cfg in each of the specified args and upwards. If one is matched, it becomes the ini-file and its directory becomes the rootdir.
• if no ini-file was found, use the already determined common ancestor as root directory. This allows the use of pytest in structures that are not part of a package and don’t have any particular ini-file configuration.

If no args are given, pytest collects test below the current working directory and also starts determining the rootdir from there.

warning:custom pytest plugin commandline arguments may include a path, as in pytest --log-output ../../test.log args. Then args is mandatory, otherwise pytest uses the folder of test.log for rootdir determination (see also issue 1435). A dot . for referencing to the current working directory is also possible.

Note that an existing pytest.ini file will always be considered a match, whereas tox.ini and setup.cfg will only match if they contain a [pytest] or [tool:pytest] section, respectively. Options from multiple ini-files candidates are never merged - the first one wins (pytest.ini always wins, even if it does not contain a [pytest] section).

The config object will subsequently carry these attributes:

• config.rootdir: the determined root directory, guaranteed to exist.
• config.inifile: the determined ini-file, may be None.

The rootdir is used a reference directory for constructing test addresses (“nodeids”) and can be used also by plugins for storing per-testrun information.

Example:

pytest path/to/testdir path/other/

will determine the common ancestor as path and then check for ini-files as follows:

# first look for pytest.ini files
path/pytest.ini
path/setup.cfg  # must also contain [tool:pytest] section to match
path/tox.ini    # must also contain [pytest] section to match
pytest.ini
... # all the way down to the root

# now look for setup.py
path/setup.py
setup.py
... # all the way down to the root

How to change command line options defaults

It can be tedious to type the same series of command line options every time you use pytest. For example, if you always want to see detailed info on skipped and xfailed tests, as well as have terser “dot” progress output, you can write it into a configuration file:

# content of pytest.ini
# (or tox.ini or setup.cfg)
[pytest]
addopts = -ra -q

Alternatively, you can set a PYTEST_ADDOPTS environment variable to add command line options while the environment is in use:

export PYTEST_ADDOPTS="-v"

Here’s how the command-line is built in the presence of addopts or the environment variable:

<pytest.ini:addopts> $PYTEST_ADDOTPS <extra command-line arguments>

So if the user executes in the command-line:

pytest -m slow

The actual command line executed is:

pytest -ra -q -v -m slow

Note that as usual for other command-line applications, in case of conflicting options the last one wins, so the example above will show verbose output because -v overwrites -q.

Builtin configuration file options

minversion

Specifies a minimal pytest version required for running tests.

minversion = 2.1 # will fail if we run with pytest-2.0

addopts

Add the specified OPTS to the set of command line arguments as if they had been specified by the user. Example: if you have this ini file content:

[pytest]
addopts = --maxfail=2 -rf  # exit after 2 failures, report fail info

issuing pytest test_hello.py actually means:

pytest --maxfail=2 -rf test_hello.py

Default is to add no options.

norecursedirs

Set the directory basename patterns to avoid when recursing for test discovery. The individual (fnmatch-style) patterns are applied to the basename of a directory to decide if to recurse into it. Pattern matching characters:

*       matches everything
?       matches any single character
[seq]   matches any character in seq
[!seq]  matches any char not in seq

Default patterns are '.*', 'build', 'dist', 'CVS', '_darcs', '{arch}', '*.egg', 'venv'. Setting a norecursedirs replaces the default. Here is an example of how to avoid certain directories:

# content of pytest.ini
[pytest]
norecursedirs = .svn _build tmp*

This would tell pytest to not look into typical subversion or sphinx-build directories or into any tmp prefixed directory.

Additionally, pytest will attempt to intelligently identify and ignore a virtualenv by the presence of an activation script. Any directory deemed to be the root of a virtual environment will not be considered during test collection unless ‑‑collect‑in‑virtualenv is given. Note also that norecursedirs takes precedence over ‑‑collect‑in‑virtualenv; e.g. if you intend to run tests in a virtualenv with a base directory that matches '.*' you must override norecursedirs in addition to using the ‑‑collect‑in‑virtualenv flag.

testpaths

New in version 2.8.

Sets list of directories that should be searched for tests when no specific directories, files or test ids are given in the command line when executing pytest from the rootdir directory. Useful when all project tests are in a known location to speed up test collection and to avoid picking up undesired tests by accident.

# content of pytest.ini
[pytest]
testpaths = testing doc

This tells pytest to only look for tests in testing and doc directories when executing from the root directory.

python_files

One or more Glob-style file patterns determining which python files are considered as test modules.

python_classes

One or more name prefixes or glob-style patterns determining which classes are considered for test collection. Here is an example of how to collect tests from classes that end in Suite:

# content of pytest.ini
[pytest]
python_classes = *Suite

Note that unittest.TestCase derived classes are always collected regardless of this option, as unittest‘s own collection framework is used to collect those tests.

python_functions

One or more name prefixes or glob-patterns determining which test functions and methods are considered tests. Here is an example of how to collect test functions and methods that end in _test:

# content of pytest.ini
[pytest]
python_functions = *_test

Note that this has no effect on methods that live on a unittest .TestCase derived class, as unittest‘s own collection framework is used to collect those tests.

See Changing naming conventions for more detailed examples.

doctest_optionflags

One or more doctest flag names from the standard doctest module. See how pytest handles doctests.

confcutdir

Sets a directory where search upwards for conftest.py files stops. By default, pytest will stop searching for conftest.py files upwards from pytest.ini/tox.ini/setup.cfg of the project if any, or up to the file-system root.

filterwarnings

New in version 3.1.

Sets a list of filters and actions that should be taken for matched warnings. By default all warnings emitted during the test session will be displayed in a summary at the end of the test session.

# content of pytest.ini
[pytest]
filterwarnings =
    error
    ignore::DeprecationWarning

This tells pytest to ignore deprecation warnings and turn all other warnings into errors. For more information please refer to Warnings Capture.

cache_dir

New in version 3.2.

Sets a directory where stores content of cache plugin. Default directory is .cache which is created in rootdir. Directory may be relative or absolute path. If setting relative path, then directory is created relative to rootdir. Additionally path may contain environment variables, that will be expanded. For more information about cache plugin please refer to Cache: working with cross-testrun state.