xenial (1) py.test-2.7.1.gz

Provided by: python-pytest_2.8.7-4_all bug

NAME

       pytest - pytest usage

CALLING PY.TEST THROUGH PYTHON -M PY.TEST

       New in version 2.0.

       If  you  use  Python-2.5  or later you can invoke testing through the Python interpreter from the command
       line:

          python -m pytest [...]

       This is equivalent to invoking the command line script py.test [...]  directly.

GETTING HELP ON VERSION, OPTION NAMES, ENVIRONMENT VARIABLES

          py.test --version   # shows where pytest was imported from
          py.test --fixtures  # show available builtin function arguments
          py.test -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:

          py.test -x            # stop after first failure
          py.test --maxfail=2    # stop after two failures

SPECIFYING TESTS / SELECTING TESTS

       Several test run options:

          py.test test_mod.py   # run tests in module
          py.test somepath      # run all tests below somepath
          py.test -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
          py.test 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
          py.test 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:

          py.test --pyargs pkg # run all tests found below directory of pypkg

MODIFYING PYTHON TRACEBACK PRINTING

       Examples for modifying traceback printing:

          py.test --showlocals # show local variables in tracebacks
          py.test -l           # show local variables (shortcut)

          py.test --tb=long    # the default informative traceback formatting
          py.test --tb=native  # the Python standard library formatting
          py.test --tb=short   # a shorter traceback format
          py.test --tb=line    # only one line per failure

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:

          py.test --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:

          py.test -x --pdb   # drop to PDB on first failure, then end test session
          py.test --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

       Prior to pytest version 2.0.0 you could only enter PDB tracing if you disabled capturing on  the  command
       line  via  py.test -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.

       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 py.test -s.

PROFILING TEST EXECUTION DURATION

       To get a list of the slowest 10 test durations:

          py.test --durations=10

CREATING JUNITXML FORMAT FILES

       To create result files which can be read by Hudson or other  Continuous  integration  servers,  use  this
       invocation:

          py.test --junitxml=path

       to create an XML file at path.

   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:
          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.

CREATING RESULTLOG FORMAT FILES

       To create plain-text machine-readable result files you can issue:

          py.test --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:

          py.test --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:

          py.test --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 py.test like this:

          py.test -p no:doctest

CALLING PY.TEST 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 "py.test" 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'])

       or pass in a string:

          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

AUTHOR

       holger krekel at merlinux eu

       2015, holger krekel and pytest-dev team