pytest-ansible
This repository contains a plugin for pytest which adds several fixtures
for running ansible modules, or inspecting ansible_facts. While one
can simply call out to ansible using the subprocess module, having to
parse stdout to determine the outcome of the operation is unpleasant and prone
to error. With pytest-ansible, modules return JSON data which you can
inspect and act on, much like with an ansible
playbook.
Installation
Install this plugin using pip
pip install pytest-ansibleUsage
Once installed, the following pytest command-line parameters are available:
pytest \
[--inventory <path_to_inventory>] \
[--extra-inventory <path_to_extra_inventory>] \
[--host-pattern <host-pattern>] \
[--connection <plugin>] \
[--module-path <path_to_modules] \
[--user <username>] \
[--become] \
[--become-user <username>] \
[--become-method <method>] \
[--limit <limit>] \
[--check]Inventory
Using ansible first starts with defining your inventory. This can be done
several ways, but to start, we'll use the ansible_adhoc fixture.
def test_my_inventory(ansible_adhoc):
hosts = ansible_adhoc()In the example above, the hosts variable is an instance of the HostManager
class and describes your ansible inventory. For this to work, you'll need to
tell ansible where to find your inventory. Inventory can be anything
supported by ansible, which includes an INI
file or an
executable script that returns properly formatted
JSON.
For example,
pytest --inventory my_inventory.ini --host-pattern allor
pytest --inventory path/to/my/script.py --host-pattern webserversor
pytest --inventory one.example.com,two.example.com --host-pattern allIn the above examples, the inventory provided at runtime will be used in all
tests that use the ansible_adhoc fixture. A more realistic scenario may
involve using different inventory files (or host patterns) with different
tests. To accomplish this, the fixture ansible_adhoc allows you to customize
the inventory parameters. Read on for more detail on using the ansible_adhoc
fixture.
Extra Inventory
Using ansible first starts with defining your extra inventory. This feature was added in version 2.3.0, and is intended
to allow the user to work with two different inventories. This can be done in several ways, but to start,
we'll use the ansible_adhoc fixture.
For example,
pytest --inventory my_inventory.ini --extra-inventory my_second_inventory.ini --host-pattern host_in_second_inventoryFixture ansible_adhoc
The ansible_adhoc fixture returns a function used to initialize
a HostManager object. The ansible_adhoc fixture will default to parameters
supplied to the pytest command-line, but also allows one to provide keyword
arguments used to initialize the inventory.
The example below demonstrates basic usage with options supplied at run-time to
pytest.
def test_all_the_pings(ansible_adhoc):
ansible_adhoc().all.ping()The following example demonstrates available keyword arguments when creating
a HostManager object.
def test_uptime(ansible_adhoc):
# take down the database
ansible_adhoc(inventory='db1.example.com,', user='ec2-user',
become=True, become_user='root').all.command('reboot')The HostManager object returned by the ansible_adhoc() function provides
numerous ways of calling ansible modules against some, or all, of the
inventory. The following demonstates sample usage.
def test_host_manager(ansible_adhoc):
hosts = ansible_adhoc()
# __getitem__
hosts['all'].ping()
hosts['localhost'].ping()
# __getattr__
hosts.all.ping()
hosts.localhost.ping()
# Supports [ansible host patterns](http://docs.ansible.com/ansible/latest/intro_patterns.html)
hosts['webservers:!phoenix'].ping() # all webservers that are not in phoenix
hosts[0].ping()
hosts[0:2].ping()
assert 'one.example.com' in hosts
assert hasattr(hosts, 'two.example.com')
for a_host in hosts:
a_host.ping()Fixture localhost
The localhost fixture is a convenience fixture that surfaces
a ModuleDispatcher instance for ansible host running pytest. This is
convenient when using ansible modules that typically run on the local machine,
such as cloud modules (ec2, gce etc...).
def test_do_something_cloudy(localhost, ansible_adhoc):
"""Deploy an ec2 instance using multiple fixtures."""
params = dict(
key_name='somekey',
instance_type='t2.micro',
image='ami-123456',
wait=True,
group='webserver',
count=1,
vpc_subnet_id='subnet-29e63245',
assign_public_ip=True,
)
# Deploy an ec2 instance from localhost using the `ansible_adhoc` fixture
ansible_adhoc(inventory='localhost,', connection='local').localhost.ec2(**params)
# Deploy an ec2 instance from localhost using the `localhost` fixture
localhost.ec2(**params)Fixture ansible_module
The ansible_module fixture allows tests and fixtures to call ansible
modules. Unlike the ansible_adhoc
fixture, this fixture only uses the options supplied to pytest at run time.
A very basic example demonstrating the ansible ping module:
def test_ping(ansible_module):
ansible_module.ping()A more involved example of updating the sshd configuration, and restarting the service.
def test_sshd_config(ansible_module):
# update sshd MaxSessions
contacted = ansible_module.lineinfile(
dest="/etc/ssh/sshd_config",
regexp="^#?MaxSessions .*",
line="MaxSessions 150")
)
# assert desired outcome
for (host, result) in contacted.items():
assert 'failed' not in result, result['msg']
assert 'changed' in result
# restart sshd
contacted = ansible_module.service(
name="sshd",
state="restarted"
)
# assert successful restart
for (host, result) in contacted.items():
assert 'changed' in result and result['changed']
assert result['name'] == 'sshd'
# do other stuff ...Fixture ansible_facts
The ansible_facts fixture returns a JSON structure representing the system
facts for the associated inventory. Sample fact data is available in the
ansible
documentation.
Note, this fixture is provided for convenience and could easily be called using
ansible_module.setup().
A systems facts can be useful when deciding whether to skip a test ...
def test_something_with_amazon_ec2(ansible_facts):
for facts in ansible_facts:
if 'ec2.internal' != facts['ansible_domain']:
pytest.skip("This test only applies to ec2 instances")Additionally, since facts are just ansible modules, you could inspect the
contents of the ec2_facts module for greater granularity ...
def test_terminate_us_east_1_instances(ansible_adhoc):
for facts in ansible_adhoc().all.ec2_facts():
if facts['ansible_ec2_placement_region'].startswith('us-east'):
'''do some testing'''Parameterizing with pytest.mark.ansible
Perhaps the --ansible-inventory=<inventory> includes many systems, but you
only wish to interact with a subset. The pytest.mark.ansible marker can be
used to modify the pytest-ansible command-line parameters for a single
test. Please note, the fixture ansible_adhoc is the prefer mechanism for
interacting with ansible inventory within tests.
For example, to interact with the local system, you would adjust the
host_pattern and connection parameters.
@pytest.mark.ansible(host_pattern='local,', connection='local')
def test_copy_local(ansible_module):
# create a file with random data
contacted = ansible_module.copy(
dest='/etc/motd',
content='PyTest is amazing!',
owner='root',
group='root',
mode='0644',
)
# assert only a single host was contacted
assert len(contacted) == 1, \
"Unexpected number of hosts contacted (%d != %d)" % \
(1, len(contacted))
assert 'local' in contacted
# assert the copy module reported changes
assert 'changed' in contacted['local']
assert contacted['local']['changed']Note, the parameters provided by pytest.mark.ansible will apply to all
class methods.
@pytest.mark.ansible(host_pattern='local,', connection='local')
class Test_Local(object):
def test_install(self, ansible_module):
'''do some testing'''
def test_template(self, ansible_module):
'''do some testing'''
def test_service(self, ansible_module):
'''do some testing'''Inspecting results
When using the ansible_adhoc, localhost or ansible_module fixtures, the
object returned will be an instance of class AdHocResult. The
AdHocResult class can be inspected as follows:
def test_adhoc_result(ansible_adhoc):
contacted = ansible_adhoc(inventory=my_inventory).command("date")
# As a dictionary
for (host, result) in contacted.items():
assert result.is_successful, "Failed on host %s" % host
for result in contacted.values():
assert result.is_successful
for host in contacted.keys():
assert host in ['localhost', 'one.example.com']
assert contacted.localhost.is_successful
# As a list
assert len(contacted) > 0
assert 'localhost' in contacted
# As an iterator
for result in contacted:
assert result.is_successful
# With __getattr__
assert contacted.localhost.is_successful
# Or __gettem__
assert contacted['localhost'].is_successfulUsing the AdHocResult object provides ways to conveniently access results
for different hosts involved in the ansible adhoc command. Once the specific
host result is found, you may inspect the result of the ansible adhoc command
on that use by way of the ModuleResult interface. The ModuleResult
class represents the dictionary returned by the ansible module for a particular
host. The contents of the dictionary depend on the module called.
The ModuleResult interface provides some convenient proprerties to
determine the success of the module call. Examples are included below.
def test_module_result(localhost):
contacted = localhost.command("find /tmp")
assert contacted.localhost.is_successful
assert contacted.localhost.is_ok
assert contacted.localhost.is_changed
assert not contacted.localhost.is_failed
contacted = localhost.shell("exit 1")
assert contacted.localhost.is_failed
assert not contacted.localhost.is_successfulThe contents of the JSON returned by an ansible module differs from module to module. For guidance, consult the documentation and examples for the specific ansible module.
Exception handling
If ansible is unable to connect to any inventory, an exception will be raised.
@pytest.mark.ansible(inventory='unreachable.example.com,')
def test_shutdown(ansible_module):
# attempt to ping a host that is down (or doesn't exist)
pytest.raises(pytest_ansible.AnsibleHostUnreachable):
ansible_module.ping()Sometimes, only a single host is unreachable, and others will have properly returned data. The following demonstrates how to catch the exception, and inspect the results.
@pytest.mark.ansible(inventory='good:bad')
def test_inventory_unreachable(ansible_module):
exc_info = pytest.raises(pytest_ansible.AnsibleHostUnreachable, ansible_module.ping)
(contacted, dark) = exc_info.value.results
# inspect the JSON result...
for (host, result) in contacted.items():
assert result['ping'] == 'pong'
for (host, result) in dark.items():
assert result['failed'] == True