Developer documentation
* Turns TESTING into a rst file, that we include in the developer documentation, for instructions on how to run the unit tests. * Link to a Vagrant project that sets up Neutron inside a VM. * Adds a section for how to debug with Nose * Add new section for Neutron Internals * Neutron L2 Agent documentation - currently only OVS * Make the Security Group API extension an example of how an API extension is implemented Implements bp developer-documentation Change-Id: I9b452abc9da3b1a41ae65cff727967de0eab12fe
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Sean M. Collins
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TESTING.rst
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TESTING.rst
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Testing Neutron
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=============================================================
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Overview
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--------
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The unit tests are meant to cover as much code as possible and should
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be executed without the service running. They are designed to test
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the various pieces of the neutron tree to make sure any new changes
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don't break existing functionality.
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The functional tests are intended to validate actual system
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interaction. Mocks should be used sparingly, if at all. Care
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should be taken to ensure that existing system resources are not
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modified and that resources created in tests are properly cleaned
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up.
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Development process
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-------------------
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It is expected that any new changes that are proposed for merge
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come with tests for that feature or code area. Ideally any bugs
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fixes that are submitted also have tests to prove that they stay
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fixed! In addition, before proposing for merge, all of the
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current tests should be passing.
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Virtual environments
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~~~~~~~~~~~~~~~~~~~~
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Testing OpenStack projects, including Neutron, is made easier with `DevStack <https://github.com/openstack-dev/devstack>`_.
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Create a machine (such as a VM or Vagrant box) running a distribution supported
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by DevStack and install DevStack there. For example, there is a Vagrant script
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for DevStack at https://github.com/bcwaldon/vagrant_devstack.
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.. note::
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If you prefer not to use DevStack, you can still check out source code on your local
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machine and develop from there.
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Running unit tests
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------------------
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There are three mechanisms for running tests: run_tests.sh, tox,
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and nose. Before submitting a patch for review you should always
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ensure all test pass; a tox run is triggered by the jenkins gate
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executed on gerrit for each patch pushed for review.
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With these mechanisms you can either run the tests in the standard
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environment or create a virtual environment to run them in.
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By default after running all of the tests, any pep8 errors
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found in the tree will be reported.
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With `run_tests.sh`
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~~~~~~~~~~~~~~~~~~~
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You can use the `run_tests.sh` script in the root source directory to execute
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tests in a virtualenv::
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./run_tests -V
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With `nose`
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~~~~~~~~~~~
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You can use `nose`_ to run individual tests, as well as use for debugging
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portions of your code::
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source .venv/bin/activate
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pip install nose
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nosetests
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There are disadvantages to running Nose - the tests are run sequentially, so
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race condition bugs will not be triggered, and the full test suite will
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take significantly longer than tox & testr. The upside is that testr has
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some rough edges when it comes to diagnosing errors and failures, and there is
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no easy way to set a breakpoint in the Neutron code, and enter an
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interactive debugging session while using testr.
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.. _nose: https://nose.readthedocs.org/en/latest/index.html
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With `tox`
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~~~~~~~~~~
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Neutron, like other OpenStack projects, uses `tox`_ for managing the virtual
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environments for running test cases. It uses `Testr`_ for managing the running
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of the test cases.
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Tox handles the creation of a series of `virtualenvs`_ that target specific
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versions of Python (2.6, 2.7, 3.3, etc).
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Testr handles the parallel execution of series of test cases as well as
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the tracking of long-running tests and other things.
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Running unit tests is as easy as executing this in the root directory of the
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Neutron source code::
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tox
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For more information on the standard Tox-based test infrastructure used by
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OpenStack and how to do some common test/debugging procedures with Testr,
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see this wiki page:
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https://wiki.openstack.org/wiki/Testr
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.. _Testr: https://wiki.openstack.org/wiki/Testr
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.. _tox: http://tox.readthedocs.org/en/latest/
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.. _virtualenvs: https://pypi.python.org/pypi/virtualenv
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Running individual tests
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~~~~~~~~~~~~~~~~~~~~~~~~
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For running individual test modules or cases, you just need to pass
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the dot-separated path to the module you want as an argument to it.
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For executing a specific test case, specify the name of the test case
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class separating it from the module path with a colon.
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For example, the following would run only the JSONV2TestCase tests from
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neutron/tests/unit/test_api_v2.py::
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$ ./run_tests.sh neutron.tests.unit.test_api_v2:JSONV2TestCase
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or::
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$ ./tox neutron.tests.unit.test_api_v2:JSONV2TestCase
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Adding more tests
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~~~~~~~~~~~~~~~~~
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Neutron has a fast growing code base and there is plenty of areas that
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need to be covered by unit and functional tests.
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To get a grasp of the areas where tests are needed, you can check
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current coverage by running::
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$ ./run_tests.sh -c
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Debugging
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---------
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By default, calls to pdb.set_trace() will be ignored when tests
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are run. For pdb statements to work, invoke run_tests as follows::
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$ ./run_tests.sh -d [test module path]
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It's possible to debug tests in a tox environment::
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$ tox -e venv -- python -m testtools.run [test module path]
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Tox-created virtual environments (venv's) can also be activated
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after a tox run and reused for debugging::
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$ tox -e venv
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$ . .tox/venv/bin/activate
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$ python -m testtools.run [test module path]
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Tox packages and installs the neutron source tree in a given venv
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on every invocation, but if modifications need to be made between
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invocation (e.g. adding more pdb statements), it is recommended
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that the source tree be installed in the venv in editable mode::
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# run this only after activating the venv
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$ pip install --editable .
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Editable mode ensures that changes made to the source tree are
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automatically reflected in the venv, and that such changes are not
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overwritten during the next tox run.
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Post-mortem debugging
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~~~~~~~~~~~~~~~~~~~~~
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Setting OS_POST_MORTEM_DEBUG=1 in the shell environment will ensure
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that pdb.post_mortem() will be invoked on test failure::
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$ OS_POST_MORTEM_DEBUG=1 ./run_tests.sh -d [test module path]
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