test_ok2/doc/en/example/pythoncollection.rst

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Changing standard (Python) test discovery
===============================================
Ignore paths during test collection
-----------------------------------
You can easily ignore certain test directories and modules during collection
by passing the ``--ignore=path`` option on the cli. ``pytest`` allows multiple
``--ignore`` options. Example:
.. code-block:: text
tests/
|-- example
| |-- test_example_01.py
| |-- test_example_02.py
| '-- test_example_03.py
|-- foobar
| |-- test_foobar_01.py
| |-- test_foobar_02.py
| '-- test_foobar_03.py
'-- hello
'-- world
|-- test_world_01.py
|-- test_world_02.py
'-- test_world_03.py
Now if you invoke ``pytest`` with ``--ignore=tests/foobar/test_foobar_03.py --ignore=tests/hello/``,
you will see that ``pytest`` only collects test-modules, which do not match the patterns specified:
.. code-block:: pytest
=========================== test session starts ============================
platform linux -- Python 3.x.y, pytest-5.x.y, py-1.x.y, pluggy-0.x.y
rootdir: $REGENDOC_TMPDIR, inifile:
collected 5 items
tests/example/test_example_01.py . [ 20%]
tests/example/test_example_02.py . [ 40%]
tests/example/test_example_03.py . [ 60%]
tests/foobar/test_foobar_01.py . [ 80%]
tests/foobar/test_foobar_02.py . [100%]
========================= 5 passed in 0.02 seconds =========================
The ``--ignore-glob`` option allows to ignore test file paths based on Unix shell-style wildcards.
If you want to exclude test-modules that end with ``_01.py``, execute ``pytest`` with ``--ignore-glob='*_01.py'``.
Deselect tests during test collection
-------------------------------------
Tests can individually be deselected during collection by passing the ``--deselect=item`` option.
For example, say ``tests/foobar/test_foobar_01.py`` contains ``test_a`` and ``test_b``.
You can run all of the tests within ``tests/`` *except* for ``tests/foobar/test_foobar_01.py::test_a``
by invoking ``pytest`` with ``--deselect tests/foobar/test_foobar_01.py::test_a``.
``pytest`` allows multiple ``--deselect`` options.
Keeping duplicate paths specified from command line
----------------------------------------------------
Default behavior of ``pytest`` is to ignore duplicate paths specified from the command line.
Example:
.. code-block:: pytest
pytest path_a path_a
...
collected 1 item
...
Just collect tests once.
To collect duplicate tests, use the ``--keep-duplicates`` option on the cli.
Example:
.. code-block:: pytest
pytest --keep-duplicates path_a path_a
...
collected 2 items
...
As the collector just works on directories, if you specify twice a single test file, ``pytest`` will
still collect it twice, no matter if the ``--keep-duplicates`` is not specified.
Example:
.. code-block:: pytest
pytest test_a.py test_a.py
...
collected 2 items
...
Changing directory recursion
-----------------------------------------------------
You can set the :confval:`norecursedirs` option in an ini-file, for example your ``pytest.ini`` in the project root directory:
.. code-block:: ini
# content of pytest.ini
[pytest]
norecursedirs = .svn _build tmp*
This would tell ``pytest`` to not recurse into typical subversion or sphinx-build directories or into any ``tmp`` prefixed directory.
.. _`change naming conventions`:
Changing naming conventions
-----------------------------------------------------
You can configure different naming conventions by setting
the :confval:`python_files`, :confval:`python_classes` and
:confval:`python_functions` in your :ref:`configuration file <config file formats>`.
Here is an example:
.. code-block:: ini
# content of pytest.ini
# Example 1: have pytest look for "check" instead of "test"
[pytest]
python_files = check_*.py
python_classes = Check
python_functions = *_check
This would make ``pytest`` look for tests in files that match the ``check_*
.py`` glob-pattern, ``Check`` prefixes in classes, and functions and methods
that match ``*_check``. For example, if we have:
.. code-block:: python
# content of check_myapp.py
class CheckMyApp:
def simple_check(self):
pass
def complex_check(self):
pass
The test collection would look like this:
.. code-block:: pytest
$ pytest --collect-only
=========================== test session starts ============================
platform linux -- Python 3.x.y, pytest-8.x.y, pluggy-1.x.y
rootdir: /home/sweet/project
configfile: pytest.ini
collected 2 items
<Dir pythoncollection.rst-196>
<Module check_myapp.py>
<Class CheckMyApp>
<Function simple_check>
<Function complex_check>
======================== 2 tests collected in 0.12s ========================
You can check for multiple glob patterns by adding a space between the patterns:
.. code-block:: ini
# Example 2: have pytest look for files with "test" and "example"
# content of pytest.ini
[pytest]
python_files = test_*.py example_*.py
.. note::
the ``python_functions`` and ``python_classes`` options has no effect
for ``unittest.TestCase`` test discovery because pytest delegates
discovery of test case methods to unittest code.
Interpreting cmdline arguments as Python packages
-----------------------------------------------------
You can use the ``--pyargs`` option to make ``pytest`` try
interpreting arguments as python package names, deriving
their file system path and then running the test. For
example if you have unittest2 installed you can type:
.. code-block:: bash
pytest --pyargs unittest2.test.test_skipping -q
which would run the respective test module. Like with
other options, through an ini-file and the :confval:`addopts` option you
can make this change more permanently:
.. code-block:: ini
# content of pytest.ini
[pytest]
addopts = --pyargs
Now a simple invocation of ``pytest NAME`` will check
if NAME exists as an importable package/module and otherwise
treat it as a filesystem path.
Finding out what is collected
-----------------------------------------------
You can always peek at the collection tree without running tests like this:
.. code-block:: pytest
. $ pytest --collect-only pythoncollection.py
=========================== test session starts ============================
platform linux -- Python 3.x.y, pytest-8.x.y, pluggy-1.x.y
rootdir: /home/sweet/project
configfile: pytest.ini
collected 3 items
<Dir pythoncollection.rst-196>
<Dir CWD>
<Module pythoncollection.py>
<Function test_function>
<Class TestClass>
<Function test_method>
<Function test_anothermethod>
======================== 3 tests collected in 0.12s ========================
.. _customizing-test-collection:
Customizing test collection
---------------------------
.. regendoc:wipe
You can easily instruct ``pytest`` to discover tests from every Python file:
.. code-block:: ini
# content of pytest.ini
[pytest]
python_files = *.py
However, many projects will have a ``setup.py`` which they don't want to be
imported. Moreover, there may files only importable by a specific python
version. For such cases you can dynamically define files to be ignored by
listing them in a ``conftest.py`` file:
.. code-block:: python
# content of conftest.py
import sys
collect_ignore = ["setup.py"]
if sys.version_info[0] > 2:
collect_ignore.append("pkg/module_py2.py")
and then if you have a module file like this:
.. code-block:: python
# content of pkg/module_py2.py
def test_only_on_python2():
try:
assert 0
except Exception, e:
pass
and a ``setup.py`` dummy file like this:
.. code-block:: python
# content of setup.py
0 / 0 # will raise exception if imported
If you run with a Python 2 interpreter then you will find the one test and will
leave out the ``setup.py`` file:
.. code-block:: pytest
#$ pytest --collect-only
====== test session starts ======
platform linux2 -- Python 2.7.10, pytest-2.9.1, py-1.4.31, pluggy-0.3.1
rootdir: $REGENDOC_TMPDIR, inifile: pytest.ini
collected 1 items
<Module 'pkg/module_py2.py'>
<Function 'test_only_on_python2'>
====== 1 tests found in 0.04 seconds ======
If you run with a Python 3 interpreter both the one test and the ``setup.py``
file will be left out:
.. code-block:: pytest
$ pytest --collect-only
=========================== test session starts ============================
platform linux -- Python 3.x.y, pytest-8.x.y, pluggy-1.x.y
rootdir: /home/sweet/project
configfile: pytest.ini
collected 0 items
======================= no tests collected in 0.12s ========================
It's also possible to ignore files based on Unix shell-style wildcards by adding
patterns to :globalvar:`collect_ignore_glob`.
The following example ``conftest.py`` ignores the file ``setup.py`` and in
addition all files that end with ``*_py2.py`` when executed with a Python 3
interpreter:
.. code-block:: python
# content of conftest.py
import sys
collect_ignore = ["setup.py"]
if sys.version_info[0] > 2:
collect_ignore_glob = ["*_py2.py"]
Since Pytest 2.6, users can prevent pytest from discovering classes that start
with ``Test`` by setting a boolean ``__test__`` attribute to ``False``.
.. code-block:: python
# Will not be discovered as a test
class TestClass:
__test__ = False