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(Added Test-runner as a proposal to terms list)
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= Standard Test Interface =
Moved to:
Standard Discovery, Staging and Invocation of Integration Tests.
== Summary ==
Let's define a clear delineation of between a ''test suite'' (including framework) and the CI system that is running the test suite. This is the standard interface. What follows is a standard way to discover, package and invoke integration tests for a package stored in a Fedora dist-git repo.
Many Fedora packages have unit tests. These tests are typically run during a <code>%check</code> RPM build step and run in a build root. On the other hand, integration testing should happen against a composed system. Upstream projects have integration tests, both Fedora QA and the Atomic Host team would like to create more integration tests, Red Hat would like to bring integration tests upstream.
== Benefit to Fedora ==
Developers benefit by having a consistent target for how to describe tests, while also being able to execute them locally while debugging issues or iterating on tests.
By staging and invoking tests consistently in Fedora we create an eco-system for the tests that allows varied test frameworks as well as CI system infrastructure to interoperate. The integration tests outlast the implementation details of either the frameworks they're written in or the CI systems running them.
== Terminology ==
* '''Test Subject''': The items that are to be tested.
** Examples: RPMs, OCI image, ISO, QCow2, Module repository ...
* '''Test''': A callable/runnable piece of code and corresponding test data and mocks which exercises and evaluates a ''test subject''.
** '''Test environment''': environment where actual test run takes place. Test has direct impact on test environment.
* '''Test Suite''': The collection of all tests that apply to a ''test subject''.
* '''Test Framework''': A library or component that the ''test suite'' and ''tests'' use to accomplish their job.
** Examples: [ Avocado], [ GNOME Installed Tests], [ Meta Test Family], [ Ansible tests in Atomic Host], [ Tunir tests], docker test images, ...
* '''Test Result''': A boolean pass/fail output of a ''test suite''.
** ''Test results'' are for consumption by automated aspects of a ''testing systems''.
* '''Test Artifact''': Any additional output of the test suite such as the stdout/stderr output, log files, screenshots, core dumps, or TAP/Junit/subunit streams.
** ''Test artifacts'' are for consumption by humans, archival or big data analysis.
* '''Testing System''': A CI or other ''testing system'' that would like to discover, stage and invoke tests for a ''test subject''.
** Examples: [ Jenkins], [ Taskotron], [ ZUUL], [ CentOS CI], [ Papr], [ Travis], [ Semaphore], [ Openshift CI/CD], [ Ubuntu CI], ...
** Testing system uses '''test runner''' <span style="color: red;"> / staged system</span> as a place for running tests. Testing system delegates test-running to test runner. Test runner examples: local machine, VM, ...
* <span style="color: red;">'''Test runner:''' is a system staged by testing system. This system could be different from test subjects. Usually for test-runner is used a  stable version of OS.</span>
== Responsibilities ==
The '''testing system''' is responsible to:
* Build or otherwise acquire the ''test subject'', such as a package, container image, tree …
* Decide which ''test suite'' to run, often by using the standard interface to discover appropriate ''tests'' for the dist-git repo that a test subject originated in.
* Schedule, provision or orchestrate a job to run the ''test suite'' on appropriate compute, storage, ...
* Stage the ''test suite'' as described by the ''standard interface''.
* Invoke the ''test suite'' as described by the ''standard interface''.
* Gather the ''test results'' and ''test artifacts'' as described by the ''standard interface''.
* Announce and relay the ''test results'' and ''test artifacts'' for gating, archival ...
The '''standard interface''' describes how to:
* Discover a ''test suite'' for a given dist-git repo.
* Uniquely identify a ''test suite''.
* Stage a ''test suite'' and its dependencies such as ''test frameworks''.
* Provide the ''test subject'' to the ''test suite''.
* Invoke a ''test suite'' in a consistent way.
* Gather ''test results'' and ''test artifacts'' from the invoked ''test suite''.
The '''test suite''' is responsible to:
* Declare its dependencies such as a ''test framework'' via the ''standard interface''.
* Execute the ''test framework'' as necessary.
* Provision (usually locally) any containers or virtual machines necessary for testing the ''test subject''.
* Provide ''test results'' and ''test subjects'' back according to the standard 
The format of the textual logs and ''test artifacts'' that come out of a test suite is not prescribed by this document. Nor is it envisioned to be standardized across all possible ''test suites''.
== Requirements ==
* The ''test suite'' and ''test framework'' SHOULD NOT leak its implementation details into the testing system, other than via the ''standard interface''.
* The ''test suite'' and ''test framework'' SHOULD NOT rely on the behavior of the testing system other than the ''standard interface''.
* The ''standard interface'' MUST enable a dist-git packager to run a ''test suite'' locally.
** ''Test suites'' or ''test frameworks'' MAY call out to the network for certain tasks.
* It MUST be possible to stage an upstream ''test suite'' using the ''standard interface''.
* Both ''in-situ tests'', and more rigorous ''outside-in tests'' MUST be possible with the ''standard interface''.
** For ''in-situ tests'' the ''test suite'' is in the same file system tree and process space as the ''test subject''.
** For ''outside-in tests'' the ''test suite'' is outside of the file system tree and process space of the ''test subject''.
* The ''test suite'' and ''test framework'' SHOULD be able to provision containers and virtual machines necessary for its testing without requesting them from the ''testing system''.
* The ''standard interface'' SHOULD describe how to uniquely identify a ''test suite'',
== Detailed Description ==
This standard interface describes how to discover, stage and invoke tests. It is important to cleanly separate implementation details of the ''testing system'' from the ''test suite'' and its framework. It is also important to allow Fedora packagers to locally and manually invoke a ''test suite''.
'''First see the [ Terminogy] division of [ Responsibilities] and [ Requirements]'''
=== Staging ===
Tests files will be added into the <code>tests/</code> folder of a dist-git repository branch. The structure of the files and folders is left to the liberty of the packagers but there are one or more playbooks in the <code>tests/</code> folder that can be invoked to run the test suites.
# The ''testing system'' SHOULD stage the tests on target (eg: Fedora) operating system appropriate for the branch name of the dist-git repository containing the tests.
# The ''testing system'' SHOULD stage a clean <span style="color: red;">staged</span> system / <span style="color: red;">test-runner</span> for each set of tests it runs.
# The ''testing system'' MUST stage the following packages <span style="color: red;">on test runner</span>:
## <code>ansible python2-dnf libselinux-python standard-test-roles</code>
# The ''testing system'' MUST clone the dist-git repository for the test <span style="color: red;">on test-runner</span>, and checks out the appropriate branch.
# The contents of <code>/etc/yum.repos.d</code> on the '''staged system''' SHOULD be replaced with repository information that reflects the known good Fedora packages corresponding to the branch of the dist-git repository. <span style="color: red;">We do not do this.</span>
## The ''testing system'' MAY use multiple repositories, including ''updates'' or ''updates-testing'' to ensure this.
=== Invocation ===
The testing system MUST run each playbook matching the glob <code>tests/tests*.yml</code> in the dist-git repo. Each of these files constitutes a test suite. Each test suite is invoked independently by the testing system as follows.
The ''test subjects'' are passed to the playbook and inventory as operating system environment and ansible environment. Often only one ''test subject'' is passed in. However multiple subjects may be concatenated together in a shell escaped string. The playbooks and/or inventory script split the string. The extensions as follows are used to determine the type of subject:
! Identifier !! Test subject
| *.rpm    || Absolute path to an RPM file
| *.repo    || Absolute repo filenames appropriate for <code>/etc/yum.repos.d</code>
| *.qcow2, *.qcow2c || Absolute path to one virtual machine disk image bootable with cloud-init
| *.oci    || Absolute path of one OCI container image filesystem bundle
| docker:*  || Fully qualified path to a docker image in a registry
| ...      || Other ''test subject'' identifiers may be added later.
Various ''tests'' in a playbook constitute a ''test suite''. Some parts of these ''test suites'' will run in certain contexts, against certain deliverable artifacts. Certain tests will run against Atomic Host deliverables, while others will not. Certain tests will run against Docker deliverables while others will not. This is related to, but does not exactly overlap with the ''test subject'' identifiers above. Ansible tags are used to denote these contexts.
! Tag      !! Test context
| atomic    || Atomic Host
| container || A Docker or OCI container
| classic  || Tested against a classic installed YUM/DNF installed system.
| ...      || Other ''test subject'' identifiers may be added later.
To invoke the tests, the ''testing system'' must perform the following tasks for each ''test suite'' playbook:
# MUST execute the playbook with the following operating system environment variables:
## <code>TEST_SUBJECTS</code>: The ''test subjects'' string as described above
## <code>TEST_ARTIFACTS</code>: The full path of an empty folder for ''test artifacts''
# MUST execute the playbook with the following Ansible variables.
## <code>subjects</code>: The ''test subjects'' string as described above
## <code>artifacts</code>: The full path of an empty folder for ''test artifacts''
# SHOULD execute the playbook with all Ansible tags best represent the intended ''test context''.
## The choice of ''test context'' tags is related to the ''test subject'' being tested
# MUST execute Ansible with inventory set to the full path of the file or directory <code>tests/inventory</code> if it exists.
## If the <code>tests/inventory</code> file doesn't exist, then the following inventory SHOULD be used as a default:<br> <code>/usr/share/ansible/inventory</code>
# MUST execute the playbook as root.
# MUST examine the exit code of the playbook. A zero exit code is successful ''test result'', non-zero is failure.
# MUST treat the file <code>test.log</code> in the <code>artifacts</code> folder as the main readable output of the test.
# SHOULD place the textual stdout/stderr of the <code>ansible-playbook</code> command in the <code>ansible.log</code> file in the <code>artifacts</code> folder.
# SHOULD treat the contents of the <code>artifacts</code> folder as the ''test artifacts''.
Each ''test suite'' playbook or ''test framework'' contained therein:
# SHOULD drop privileges appropriately if the ''test suite'' should be run as non-root.
# MUST install any requirements of its ''test suite'' or ''test framework'' and MUST fail if this is not possible.
# MUST provision the ''test subject'' listed in the <code>subjects</code> variable appropriately for its playbook name (described above) and MUST fail if this is not possible.
# MUST place the main readable output of the ''test suite'' into a <code>test.log</code> file in the <code>artifacts</code> variable folder. This MUST happen even if some of the test suites fail.
# SHOULD place additional ''test artifacts'' in the folder defined in the <code>artifacts</code> variable.
# MUST return a zero exit code of the playbook if the ''test result'' is a pass, or a non-zero exit code if the ''test result'' is a fail.
If an inventory file or script exists, it:
# MUST describe where to invoke the playbook and how to connect to that target.
# SHOULD launch or install any supported <code>$TEST_SUBJECTS</code> so that the playbook can be invoked against them.
# SHOULD put relevant logs in the <code>$TEST_ARTIFACTS</code> directory.
=== Discovery ===
Test discovery is done via dist-git. Both packages and modules may have tests in this format. To list which ''test context'' a given dist-git directory or playbook is relevant for, use a command like the following:
# ansible-playbook --list-tags tests.yml
== Scope ==
Since the tests are added in a sub-folder of the dist-git repo, there are no changes required to the Fedora infrastructure and will have no impact on the packagers' workflow and tooling.
Only the testing system will need to be taught to install the requirements and run the playbooks.
== User Experience ==
A standard way to package, store and run tests benefits Fedora stability, and makes Fedora better for users.
* This structure makes it easy to run locally thus potentially reproducing an error triggered on the test system.
* Ansible is being more and more popular, thus making it easier for people to contribute new tests
* Used by a lot of sys-admin, ansible could help sys-admin to bring test-cases to the packagers and developers about situation where something failed for them.
== Diagram ==
== Upgrade/compatibility impact ==
There are no real upgrade or compatibility impact. The tests will be branched per release as spec files are branched dist-git is now.
== Documentation ==
* [[CI|CI Landing page]]
* [[CI/Tests|Documentation page]]
== Proposals and Evaluation ==
During the selection process for a standard test invocation and and layout format for Fedora, [[Changes/InvokingTestsProposals|several proposals]] were examined.
== Contact ==
* Name: [[User:Stefw|Stef Walter]],
* Name: [[User:pingou|Pierre-Yves Chibon]],
* Name: [[User:astepano|Andrei Stepanov]]
* Name: [[User:sturivny|Serhii Turivnyi]],

Latest revision as of 15:49, 18 March 2019