test_ok2/doc/en/how-to/nose.rst

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.. _`noseintegration`:
How to run tests written for nose
=======================================
``pytest`` has basic support for running tests written for nose_.
.. warning::
This functionality has been deprecated and is likely to be removed in ``pytest 8.x``.
.. _nosestyle:
Usage
-------------
After :ref:`installation` type:
.. code-block:: bash
python setup.py develop # make sure tests can import our package
pytest # instead of 'nosetests'
and you should be able to run your nose style tests and
make use of pytest's capabilities.
Supported nose Idioms
----------------------
* ``setup()`` and ``teardown()`` at module/class/method level: any function or method called ``setup`` will be called during the setup phase for each test, same for ``teardown``.
* ``SkipTest`` exceptions and markers
* setup/teardown decorators
* ``__test__`` attribute on modules/classes/functions
* general usage of nose utilities
Unsupported idioms / known issues
----------------------------------
- unittest-style ``setUp, tearDown, setUpClass, tearDownClass``
are recognized only on ``unittest.TestCase`` classes but not
on plain classes. ``nose`` supports these methods also on plain
classes but pytest deliberately does not. As nose and pytest already
both support ``setup_class, teardown_class, setup_method, teardown_method``
it doesn't seem useful to duplicate the unittest-API like nose does.
If you however rather think pytest should support the unittest-spelling on
plain classes please post to :issue:`377`.
- nose imports test modules with the same import path (e.g.
``tests.test_mode``) but different file system paths
(e.g. ``tests/test_mode.py`` and ``other/tests/test_mode.py``)
by extending sys.path/import semantics. pytest does not do that. Note that
`nose2 choose to avoid this sys.path/import hackery <https://nose2.readthedocs.io/en/latest/differences.html#test-discovery-and-loading>`_.
If you place a conftest.py file in the root directory of your project
(as determined by pytest) pytest will run tests "nose style" against
the code below that directory by adding it to your ``sys.path`` instead of
running against your installed code.
You may find yourself wanting to do this if you ran ``python setup.py install``
to set up your project, as opposed to ``python setup.py develop`` or any of
the package manager equivalents. Installing with develop in a
virtual environment like tox is recommended over this pattern.
- nose-style doctests are not collected and executed correctly,
also doctest fixtures don't work.
- no nose-configuration is recognized.
- ``yield``-based methods are
fundamentally incompatible with pytest because they don't support fixtures
properly since collection and test execution are separated.
Here is a table comparing the default supported naming conventions for both
nose and pytest.
========= ========================== ======= =====
what default naming convention pytest nose
========= ========================== ======= =====
module ``test*.py``
module ``test_*.py`` ✅ ✅
module ``*_test.py``
module ``*_tests.py``
class ``*(unittest.TestCase)`` ✅ ✅
method ``test_*`` ✅ ✅
class ``Test*``
method ``test_*``
function ``test_*``
========= ========================== ======= =====
Migrating from nose to pytest
------------------------------
`nose2pytest <https://github.com/pytest-dev/nose2pytest>`_ is a Python script
and pytest plugin to help convert Nose-based tests into pytest-based tests.
Specifically, the script transforms ``nose.tools.assert_*`` function calls into
raw assert statements, while preserving format of original arguments
as much as possible.
.. _nose: https://nose.readthedocs.io/en/latest/