Provided by: python-pytest_3.3.2-2_all 
NAME
pytest - pytest usage
CALLING PYTEST THROUGH PYTHON -M PYTEST
New in version 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 calling via python will also add the current directory to sys.path.
POSSIBLE EXIT CODES
Running pytest can result in six different exit codes:
Exit code 0
All tests were collected and passed successfully
Exit code 1
Tests were collected and run but some of the tests failed
Exit code 2
Test execution was interrupted by the user
Exit code 3
Internal error happened while executing tests
Exit code 4
pytest command line usage error
Exit code 5
No tests were collected
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
Pytest supports several ways to run and select tests from the command-line.
Run tests in a module
pytest test_mod.py
Run tests in a directory
pytest testing/
Run tests by keyword expressions
pytest -k "MyClass and not method"
This will run tests which contain names that match the given string expression, which can
include Python operators that use filenames, class names and function names as variables.
The example above will run TestMyClass.test_something but not
TestMyClass.test_method_simple.
Run tests by node ids
Each collected test is assigned a unique nodeid which consist of the module filename
followed by specifiers like class names, function names and parameters from
parametrization, separated by :: characters.
To run a specific test within a module:
pytest test_mod.py::test_func
Another example specifying a test method in the command line:
pytest test_mod.py::TestClass::test_method
Run tests by marker expressions
pytest -m slow
Will run all tests which are decorated with the @pytest.mark.slow decorator.
For more information see marks.
Run tests from packages
pytest --pyargs pkg.testing
This will import pkg.testing and use its filesystem location to find and run tests from.
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
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 BREAKPOINTS
To set a breakpoint in your code use the native Python import pdb;pdb.set_trace() call in
your code and pytest automatically disables its output capture for that test:
• 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.
PROFILING TEST EXECUTION DURATION
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.
New in version 3.1.
To set the name of the root test suite xml item, you can configure the junit_suite_name
option in your config file:
[pytest]
junit_suite_name = my_suite
record_xml_property
New in version 2.8.
If you want to log additional information for a test, you can use the record_xml_property
fixture:
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:
<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:
record_xml_property 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
New in version 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
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(object):
def test_foo(self):
assert True
This will add a property node below the testsuite node to the generated 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 since version 3.0: This option is rarely used and is scheduled for removal in
4.0.
An alternative for users which still need similar functionality is to use the pytest-tap
plugin which provides a stream of test data.
If you have any concerns, please don't hesitate to open an issue.
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.
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
CALLING PYTEST FROM PYTHON CODE
New in version 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(object):
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
AUTHOR
holger krekel at merlinux eu
COPYRIGHT
2018, holger krekel and pytest-dev team