test_ok2/doc/en/usage.rst

331 lines
10 KiB
ReStructuredText

.. _usage:
Usage and Invocations
==========================================
.. _cmdline:
Calling pytest through ``python -m pytest``
-----------------------------------------------------
.. versionadded:: 2.0
You can invoke testing through the Python interpreter from the command line::
python -m pytest [...]
This is almost equivalent to invoking the command line script ``pytest [...]``
directly, except that python will also add the current directory to ``sys.path``.
Getting help on version, option names, environment variables
--------------------------------------------------------------
::
pytest --version # shows where pytest was imported from
pytest --fixtures # show available builtin function arguments
pytest -h | --help # show help on command line and config file options
Stopping after the first (or N) failures
---------------------------------------------------
To stop the testing process after the first (N) failures::
pytest -x # stop after first failure
pytest --maxfail=2 # stop after two failures
Specifying tests / selecting tests
---------------------------------------------------
Several test run options::
pytest test_mod.py # run tests in module
pytest somepath # run all tests below somepath
pytest -k stringexpr # only run tests with names that match the
# "string expression", e.g. "MyClass and not method"
# will select TestMyClass.test_something
# but not TestMyClass.test_method_simple
pytest test_mod.py::test_func # only run tests that match the "node ID",
# e.g. "test_mod.py::test_func" will select
# only test_func in test_mod.py
pytest test_mod.py::TestClass::test_method # run a single method in
# a single class
Import 'pkg' and use its filesystem location to find and run tests::
pytest --pyargs pkg # run all tests found below directory of pkg
Modifying Python traceback printing
----------------------------------------------
Examples for modifying traceback printing::
pytest --showlocals # show local variables in tracebacks
pytest -l # show local variables (shortcut)
pytest --tb=auto # (default) 'long' tracebacks for the first and last
# entry, but 'short' style for the other entries
pytest --tb=long # exhaustive, informative traceback formatting
pytest --tb=short # shorter traceback format
pytest --tb=line # only one line per failure
pytest --tb=native # Python standard library formatting
pytest --tb=no # no traceback at all
The ``--full-trace`` causes very long traces to be printed on error (longer
than ``--tb=long``). It also ensures that a stack trace is printed on
**KeyboardInterrupt** (Ctrl+C).
This is very useful if the tests are taking too long and you interrupt them
with Ctrl+C to find out where the tests are *hanging*. By default no output
will be shown (because KeyboardInterrupt is caught by pytest). By using this
option you make sure a trace is shown.
Dropping to PDB_ (Python Debugger) on failures
-----------------------------------------------
.. _PDB: http://docs.python.org/library/pdb.html
Python comes with a builtin Python debugger called PDB_. ``pytest``
allows one to drop into the PDB_ prompt via a command line option::
pytest --pdb
This will invoke the Python debugger on every failure. Often you might
only want to do this for the first failing test to understand a certain
failure situation::
pytest -x --pdb # drop to PDB on first failure, then end test session
pytest --pdb --maxfail=3 # drop to PDB for first three failures
Note that on any failure the exception information is stored on
``sys.last_value``, ``sys.last_type`` and ``sys.last_traceback``. In
interactive use, this allows one to drop into postmortem debugging with
any debug tool. One can also manually access the exception information,
for example::
>>> import sys
>>> sys.last_traceback.tb_lineno
42
>>> sys.last_value
AssertionError('assert result == "ok"',)
Setting a breakpoint / aka ``set_trace()``
----------------------------------------------------
If you want to set a breakpoint and enter the ``pdb.set_trace()`` you
can use a helper::
import pytest
def test_function():
...
pytest.set_trace() # invoke PDB debugger and tracing
.. versionadded: 2.0.0
Prior to pytest version 2.0.0 you could only enter PDB_ tracing if you disabled
capturing on the command line via ``pytest -s``. In later versions, pytest
automatically disables its output capture when you enter PDB_ tracing:
* Output capture in other tests is not affected.
* Any prior test output that has already been captured and will be processed as
such.
* Any later output produced within the same test will not be captured and will
instead get sent directly to ``sys.stdout``. Note that this holds true even
for test output occurring after you exit the interactive PDB_ tracing session
and continue with the regular test run.
.. versionadded: 2.4.0
Since pytest version 2.4.0 you can also use the native Python
``import pdb;pdb.set_trace()`` call to enter PDB_ tracing without having to use
the ``pytest.set_trace()`` wrapper or explicitly disable pytest's output
capturing via ``pytest -s``.
.. _durations:
Profiling test execution duration
-------------------------------------
.. versionadded: 2.2
To get a list of the slowest 10 test durations::
pytest --durations=10
Creating JUnitXML format files
----------------------------------------------------
To create result files which can be read by Jenkins_ or other Continuous
integration servers, use this invocation::
pytest --junitxml=path
to create an XML file at ``path``.
record_xml_property
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.. versionadded:: 2.8
If you want to log additional information for a test, you can use the
``record_xml_property`` fixture:
.. code-block:: python
def test_function(record_xml_property):
record_xml_property("example_key", 1)
assert 0
This will add an extra property ``example_key="1"`` to the generated
``testcase`` tag:
.. code-block:: xml
<testcase classname="test_function" file="test_function.py" line="0" name="test_function" time="0.0009">
<properties>
<property name="example_key" value="1" />
</properties>
</testcase>
.. warning::
This is an experimental feature, and its interface might be replaced
by something more powerful and general in future versions. The
functionality per-se will be kept, however.
Currently it does not work when used with the ``pytest-xdist`` plugin.
Also please note that using this feature will break any schema verification.
This might be a problem when used with some CI servers.
LogXML: add_global_property
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.. versionadded:: 3.0
If you want to add a properties node in the testsuite level, which may contains properties that are relevant
to all testcases you can use ``LogXML.add_global_properties``
.. code-block:: python
import pytest
@pytest.fixture(scope="session")
def log_global_env_facts(f):
if pytest.config.pluginmanager.hasplugin('junitxml'):
my_junit = getattr(pytest.config, '_xml', None)
my_junit.add_global_property('ARCH', 'PPC')
my_junit.add_global_property('STORAGE_TYPE', 'CEPH')
@pytest.mark.usefixtures(log_global_env_facts)
def start_and_prepare_env():
pass
class TestMe:
def test_foo(self):
assert True
This will add a property node below the testsuite node to the generated xml:
.. code-block:: xml
<testsuite errors="0" failures="0" name="pytest" skips="0" tests="1" time="0.006">
<properties>
<property name="ARCH" value="PPC"/>
<property name="STORAGE_TYPE" value="CEPH"/>
</properties>
<testcase classname="test_me.TestMe" file="test_me.py" line="16" name="test_foo" time="0.000243663787842"/>
</testsuite>
.. warning::
This is an experimental feature, and its interface might be replaced
by something more powerful and general in future versions. The
functionality per-se will be kept.
Creating resultlog format files
----------------------------------------------------
.. deprecated:: 3.0
This option is rarely used and is scheduled for removal in 4.0.
To create plain-text machine-readable result files you can issue::
pytest --resultlog=path
and look at the content at the ``path`` location. Such files are used e.g.
by the `PyPy-test`_ web page to show test results over several revisions.
.. _`PyPy-test`: http://buildbot.pypy.org/summary
Sending test report to online pastebin service
-----------------------------------------------------
**Creating a URL for each test failure**::
pytest --pastebin=failed
This will submit test run information to a remote Paste service and
provide a URL for each failure. You may select tests as usual or add
for example ``-x`` if you only want to send one particular failure.
**Creating a URL for a whole test session log**::
pytest --pastebin=all
Currently only pasting to the http://bpaste.net service is implemented.
Disabling plugins
-----------------
To disable loading specific plugins at invocation time, use the ``-p`` option
together with the prefix ``no:``.
Example: to disable loading the plugin ``doctest``, which is responsible for
executing doctest tests from text files, invoke pytest like this::
pytest -p no:doctest
.. _`pytest.main-usage`:
Calling pytest from Python code
----------------------------------------------------
.. versionadded:: 2.0
You can invoke ``pytest`` from Python code directly::
pytest.main()
this acts as if you would call "pytest" from the command line.
It will not raise ``SystemExit`` but return the exitcode instead.
You can pass in options and arguments::
pytest.main(['-x', 'mytestdir'])
You can specify additional plugins to ``pytest.main``::
# content of myinvoke.py
import pytest
class MyPlugin:
def pytest_sessionfinish(self):
print("*** test run reporting finishing")
pytest.main(["-qq"], plugins=[MyPlugin()])
Running it will show that ``MyPlugin`` was added and its
hook was invoked::
$ python myinvoke.py
*** test run reporting finishing
.. include:: links.inc