test_ok2/doc/en/nose.rst

.. _`noseintegration`:

Running tests written for nose
=======================================

.. include:: links.inc

``pytest`` has basic support for running tests written for nose_.

.. _nosestyle:

Usage
-------------

After :ref:`installation` type::

    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
* SkipTest exceptions and markers
* setup/teardown decorators
* ``yield``-based tests and their setup
* ``__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 this issue
  <https://github.com/pytest-dev/pytest/issues/377/>`_.

- nose imports test modules with the same import path (e.g.
  ``tests.test_mod``) 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
  but there is discussion in `issue268 <https://github.com/pytest-dev/pytest/issues/268>`_ for adding some support.  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 don't support ``setup`` properly because
  the ``setup`` method is always called in the same class instance.
  There are no plans to fix this currently because ``yield``-tests
  are deprecated in pytest 3.0, with ``pytest.mark.parametrize``
  being the recommended alternative.