Unit testing OpenStack with tox

Testing is and will always be an integral part of any software development. OpenStack is no exception. In OpenStack, unit testing is done using tox.

Installing tox,

[apt-get | yum] install python-pip; pip install tox

Tox has various tests defined in the envlist. One can open tox.ini for a complete list of envs defined.

OpenStack defines, py27 and pep8 test. Former is for unittests and later for style checks.

How to run tox and testr

Tox can use used to list unit tests and execute all of them or any subset of them using regex.

To run all tests,

tox -e py27                        # you can chose any other                                                                           environment like py26 if you like

To run only selected tests, 

tox -e py --

One can get the test_name either from the source code of the project concerned or by asking tox to list them out. For example, the tests defined in nova.tests.compute.test_compute_cells.py are accessible by 'nova.tests.unit.compute.test_compute_cells.*'. Alternatively to list the tests using tox one has to go to tox shell after sourcing the virtual env.

source .tox/py27/bin/activate

testr  list-tests

 With the venv sourced we can run testr directly.

testr help  

testr run --parallel

testr run --parallel

After tests have run you can view the failing tests then run only that list of tests.

Errors and workaround

tox requires some elaborate environment setups which can sometimes be tricky. Here are some errors whcih I came across during my installation. For posterity, I'm documenting them in this blog,

---

ERROR:

Package libvirt was not found in the pkg-config search path.

Perhaps you should add the directory containing `libvirt.pc'

to the PKG_CONFIG_PATH environment variable

Solution:

sudo yum install libvirt-devel

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ERROR:

fatal error: my_config.h: No such file or directory

 Solution:

sudo yum install mysql-devel