pytest
has basic support for running tests written for
nose.
Usage {#nosestyle}
After installation
{.interpreted-text role=“ref”} 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
-
__test__
attribute on modules/classes/functions - general usage of nose utilities
Unsupported idioms / known issues
-
unittest-style
setUp, tearDown, setUpClass, tearDownClass
are
recognized only onunittest.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
supportsetup_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. -
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
andother/tests/test_mode.py
) by extending
sys.path/import semantics. pytest does not do that but there is
discussion in
#268 for adding
some support. Note that nose2 choose to avoid this sys.path/import
hackery.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 unsupported as of pytest 4.1.0. They are
fundamentally incompatible with pytest because they don't support
fixtures properly since collection and test execution are separated.
Migrating from nose to pytest
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.