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.. _`pytest helpers`:
Pytest API and builtin fixtures
This is a list of ``pytest.*`` API functions and fixtures.
For information on plugin hooks and objects, see :ref:`plugins`.
For information on the ``pytest.mark`` mechanism, see :ref:`mark`.
For the below objects, you can also interactively ask for help, e.g. by
typing on the Python interactive prompt something like::
import pytest
.. currentmodule:: pytest
Invoking pytest interactively
.. autofunction:: main
More examples at :ref:`pytest.main-usage`
Helpers for assertions about Exceptions/Warnings
.. autofunction:: raises
Examples at :ref:`assertraises`.
.. autofunction:: deprecated_call
Raising a specific test outcome
You can use the following functions in your test, fixture or setup
functions to force a certain test outcome. Note that most often
you can rather use declarative marks, see :ref:`skipping`.
.. autofunction::
.. autofunction:: _pytest.runner.skip
.. autofunction:: _pytest.runner.importorskip
.. autofunction:: _pytest.skipping.xfail
.. autofunction:: _pytest.runner.exit
fixtures and requests
To mark a fixture function:
.. autofunction:: _pytest.python.fixture
Tutorial at :ref:`fixtures`.
The ``request`` object that can be used from fixture functions.
.. autoclass:: _pytest.python.FixtureRequest()
.. _builtinfixtures:
.. _builtinfuncargs:
Builtin fixtures/function arguments
You can ask for available builtin or project-custom
:ref:`fixtures <fixtures>` by typing::
$ py.test -q --fixtures
Return a cache object that can persist state between testing sessions.
cache.get(key, default)
cache.set(key, value)
Keys must be a ``/`` separated value, where the first part is usually the
name of your plugin or application to avoid clashes with other cache users.
Values can be any object handled by the json stdlib module.
enables capturing of writes to sys.stdout/sys.stderr and makes
captured output available via ``capsys.readouterr()`` method calls
which return a ``(out, err)`` tuple.
enables capturing of writes to file descriptors 1 and 2 and makes
captured output available via ``capfd.readouterr()`` method calls
which return a ``(out, err)`` tuple.
Fixture that adds extra xml properties to the tag for the calling test.
The fixture is callable with (name, value), with value being automatically
The returned ``monkeypatch`` funcarg provides these
helper methods to modify objects, dictionaries or os.environ::
monkeypatch.setattr(obj, name, value, raising=True)
monkeypatch.delattr(obj, name, raising=True)
monkeypatch.setitem(mapping, name, value)
monkeypatch.delitem(obj, name, raising=True)
monkeypatch.setenv(name, value, prepend=False)
monkeypatch.delenv(name, value, raising=True)
All modifications will be undone after the requesting
test function has finished. The ``raising``
parameter determines if a KeyError or AttributeError
will be raised if the set/deletion operation has no target.
the pytest config object with access to command line opts.
Return a WarningsRecorder instance that provides these methods:
* ``pop(category=None)``: return last warning matching the category.
* ``clear()``: clear list of warnings
See for information
on warning categories.
Return a TempdirFactory instance for the test session.
return a temporary directory path object
which is unique to each test function invocation,
created as a sub directory of the base temporary
directory. The returned object is a `py.path.local`_
path object.
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