Setting Up a Development Environment¶

This page describes how to setup a working Python development environment that can be used in developing Tacker on Ubuntu, Fedora or Mac OS X. These instructions assume you’re already familiar with Git and Gerrit, which is a code repository mirror and code review toolset , however if you aren’t please see this Git tutorial for an introduction to using Git and this guide for a tutorial on using Gerrit and Git for code contribution to OpenStack projects.

If you want to be able to run Tacker in a full OpenStack environment, you can use the excellent DevStack project to do so. There is a wiki page that describes setting up Tacker using DevStack.

Getting the code¶

Grab the code:

git clone https://opendev.org/openstack/tacker.git
cd tacker

Testing Tacker¶

Overview¶

The unit tests are meant to cover as much code as possible and should be executed without the service running. They are designed to test the various pieces of the tacker tree to make sure any new changes don’t break existing functionality.

The functional tests are intended to validate actual system interaction. Mocks should be used sparingly, if at all. Care should be taken to ensure that existing system resources are not modified and that resources created in tests are properly cleaned up.

Development process¶

It is expected that any new changes that are proposed for merge come with tests for that feature or code area. Ideally any bugs fixes that are submitted also have tests to prove that they stay fixed! In addition, before proposing for merge, all of the current tests should be passing.

Running unit tests with tox¶

Before submitting a patch for review you should always ensure all test pass; a tox run is triggered by the Zuul gate executed on gerrit for each patch pushed for review.

With this mechanism you can either run the tests in the standard environment or create a virtual environment to run them in.

By default after running all of the tests, any pep8 errors found in the tree will be reported.

Note that the tests can use a database, see tools/tests-setup.sh on how the databases are set up in the OpenStack CI environment.

Tacker, like other OpenStack projects, uses tox for managing the virtual environments for running test cases. It uses stestr for managing the running of the test cases.

Tox handles the creation of a series of virtualenvs that target specific versions of Python (2.7, 3.5, etc). stestr handles the parallel execution of series of test cases as well as the tracking of long-running tests and other things.

Running unit tests is as easy as executing this in the root directory of the Tacker source code:

tox

For more information on the standard Tox-based test infrastructure used by OpenStack and how to do some common test/debugging procedures with stestr, see at: https://governance.openstack.org/tc/reference/pti/python.html

Running individual tests¶

For running individual test modules or cases, you just need to pass the dot-separated path to the module you want as an argument to it.

For executing a specific test case, specify the name of the test case class separating it from the module path with a colon.

For example, the following would run only the TestVNFMPlugin tests from tacker/tests/unit/vm/test_plugin.py:

$ ./tox tacker.tests.unit.vm.test_plugin:TestVNFMPlugin

Debugging¶

It’s possible to debug tests in a tox environment:

$ tox -e venv -- python -m testtools.run [test module path]

Tox-created virtual environments (venv’s) can also be activated after a tox run and reused for debugging:

$ tox -e venv
$ . .tox/venv/bin/activate
$ python -m testtools.run [test module path]

Tox packages and installs the tacker source tree in a given venv on every invocation, but if modifications need to be made between invocation (e.g. adding more pdb statements), it is recommended that the source tree be installed in the venv in editable mode:

# run this only after activating the venv
$ pip install --editable .

Editable mode ensures that changes made to the source tree are automatically reflected in the venv, and that such changes are not overwritten during the next tox run.

Linting¶

Tacker project supports the configuration of Pylint, a lint tool for Python code.

You can get Pylint CLI tool from PyPI:

$ pip install pylint

Then you can check your code with Pylint like:

$ pylint path/to/code

If you want to check the entire Tacker code:

$ pylint tacker/

.pylintrc in Tacker repository root is a configuration file of Pylint.

If you want to check Pylint messages, detailed CLI configurations and configurations in .pylintrc, please refer to Pylint official reference.

Setting Up a Development Environment