ceph-ansible/docs/source/testing/tests.rst

.. _tests:

Tests
=====

Actual tests are written in Python methods that accept optional fixtures. These
fixtures come with interesting attributes to help with remote assertions.

As described in :ref:`test_conventions`, tests need to go into
``tests/functional/tests/``. These are collected and *mapped* to a distinct
node type, or *mapped* to run on all nodes.

Simple Python asserts are used (these tests do not need to follow the Python
``unittest.TestCase`` base class) that make it easier to reason about failures
and errors.

The test run is handled by ``py.test`` along with :ref:`testinfra` for handling
remote execution.


.. _test_files:

Test Files
----------



.. _test_fixtures:

Test Fixtures
=============

Test fixtures are a powerful feature of ``py.test`` and most tests depend on
this for making assertions about remote nodes. To request them in a test
method, all that is needed is to require it as an argument.

Fixtures are detected by name, so as long as the argument being used has the
same name, the fixture will be passed in (see `pytest fixtures`_ for more
in-depth examples). The code that follows shows a test method that will use the
``node`` fixture that contains useful information about a node in a ceph
cluster:

.. code-block:: python

   def test_ceph_conf(self, node):
       assert node['conf_path'] == "/etc/ceph/ceph.conf"

The test is naive (the configuration path might not exist remotely) but
explains how simple it is to "request" a fixture.

For remote execution, we can rely further on other fixtures (tests can have as
many fixtures as needed) like ``File``:

.. code-block:: python

   def test_ceph_config_has_inital_members_line(self, node, File):
       assert File(node["conf_path"]).contains("^mon initial members = .*$")


.. _node:

``node`` fixture
----------------

The ``node`` fixture contains a few useful pieces of information about the node
where the test is being executed, this is captured once, before tests run:

* ``address``: The IP for the ``eth1`` interface
* ``subnet``: The subnet that ``address`` belongs to
* ``vars``: all the Ansible vars set for the current run
* ``osd_ids``: a list of all the OSD IDs
* ``num_mons``: the total number of monitors for the current environment
* ``num_devices``: the number of devices for the current node
* ``num_osd_hosts``: the total number of OSD hosts
* ``total_osds``: total number of OSDs on the current node
* ``cluster_name``: the name of the Ceph cluster (which defaults to 'ceph')
* ``conf_path``: since the cluster name can change the file path for the Ceph
  configuration, this gets sets according to the cluster name.
* ``cluster_address``: the address used for cluster communication. All
  environments are set up with 2 interfaces, 1 being used exclusively for the
  cluster
* ``docker``: A boolean that identifies a Ceph Docker cluster
* ``osds``: A list of OSD IDs, unless it is a Docker cluster, where it gets the
  name of the devices (e.g. ``sda1``)


Other Fixtures
--------------

There are a lot of other fixtures provided by :ref:`testinfra` as well as
``py.test``. The full list of ``testinfra`` fixtures are available in
`testinfra_fixtures`_

``py.test`` builtin fixtures can be listed with ``pytest -q --fixtures`` and
they are described in `pytest builtin fixtures`_

.. _pytest fixtures: https://docs.pytest.org/en/latest/fixture.html
.. _pytest builtin fixtures: https://docs.pytest.org/en/latest/builtin.html#builtin-fixtures-function-arguments
.. _testinfra_fixtures: https://testinfra.readthedocs.io/en/latest/modules.html#modules