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