[Avocado-devel] RFC: Guidelines for categorizing tests

Thu May 18 14:48:16 UTC 2017

On 05/18/2017 12:22 AM, Narasimhan V wrote:
> Hi Cleber,
> 
> I agree the proposal.
> Please find some of my comments in-line.
> 

Hi Narasimhan,

Thanks for the feedback.  My responses are inline.

> On 2017-05-18 03:19, Cleber Rosa wrote:
>> Introduction
>> ============
>>
>> Avocado allows users to select tests to run based on free form "tags".
>> These tags are given as "docstring directives", that is, special
>> entries on a class or function docstring.
> 
> I like this kind of a proposal :-)
> 

I'm not sure if it was clear enough, but this functionality already
exists in Avocado:

http://avocado-framework.readthedocs.io/en/50.0/WritingTests.html#categorizing-tests

This proposal is about proposing a set of guidelines for using that feature.

>>
>> As a user of an Avocado based test suite, I'd see value in not **having**
>> to look at all the test tags before realizing that to not run tests that
>> require "super user" permissions I should run::
>>
>>   $ avocado run test.py --filter-by-tags=-root
>>
>> Instead of::
>>
>>   $ avocado run test.py --filter-by-tags=-privileged
>>
>> Not even that, by having different tests as part of the same job,
>> the following very odd sequence of command line options may be
>> needed::
>>
>>   $ avocado run test.py test2.py --filter-by-tags=-root,-privileged
>>
>> So the goal here is to let users familiar with a given Avocado based
>> test, to have fair expectations when running another Avocado based
>> tests.
>>
>> This was initially going to be a documentation update, but I felt that
>> it was not fair to make a formal proposal without without some initial
>> brainstorming.
>>
>> Proposal
>> ========
>>
>> To set the tone for my proposal, I'd like to make most things simple
>> and easy, while allowing for "everything else" to be doable.
>>
>> My general impression is that higher level information about the test
>> itself and its requirements are going to be the most commonly used
>> tags, so they must be easily set.  Some examples follow.
>>
>> Simple (standalone) tags
>> ------------------------
>>
>> Tags by functional area:
>>
>>  * cpu - Exercises a system's CPU
>>  * net - Exercises a system's network devices or networking stack
>>  * storage - Exercises a system's local storage
>>  * fs - Exercises a system's file system
>>
>> Tags by architecture:
>>
>>  * x86_64 - Requires a x86_64 architecture
>>  * ppc64 - Requries a ppc64
>>
>> Tags by access privileges:
>>
>>  * privileged - requires the test to be run with the most privileged,
>>    unrestricted privileges.  For Linux systems, this usually means the
>>    root account
>>
> 
> How are these tags going to be differentiated, ie, tag names that can be
> common across types/areas.
> Examples, if already on your mind, can help here.
> 

Well, that's exactly the point of this proposal.  If users have access
to two different test repos, and both are related to hardware/software
testing, they can expect that by choosing only tests with "cpu" tags,
they will be exercising their Central Processing Units.

Conversely, if a test repo is concerned about testing Hospital
procedures (this is very hypothetical), they may choose to use "cpu" as
a shorthand for "Care of Patients with Urgency".  They would be going
against the general Avocado guidelines, users may expect those tests to
be about "Central Processing Units", and be frustrated.

Does this example make sense?

>> Composed (key:value) tags
>> -------------------------
>>
>> The more specific tags can be achieved by composing a predefined key
>> with a value.  For instance, to tag a test as needing a specific
>> CPU flag:
>>
>>  * cpu_flag:vmx
>>
>> Or a specific PCI device:
>>
>>  * pci_id:8086:08b2
>>
>> Or even a software package:
>>
>>  * package:gcc
>>
>> Or a package group altogether:
>>
>>  * package_group:development-tools
>>
>> Some examples
>> -------------
>>
>>  * ``cpu,x86_64`` - The test exercises the CPU and requires a
>>    ``x86_64`` based platform
>>
>>  * ``net,privileged,pci_id:14e4:1657`` - The test exercises either a
>>    network device or the network stack, needs super user privileges
>>    and a "Broadcom Limited NetXtreme BCM5719 Gigabit Ethernet PCIe
>>    (rev 01)" device.
> 
> I would be interested in seeing how we can implement this.
> 
> 

We are actually free to start using this right away.  Actually, it'd be
better to start doing this once we settle on a set of guidelines.

The point is that tags are already accepted by docstring statements, and
recognized by `--filter-by-tags`.  The next evolutionary step is on the
"Do users have to provide all the ``--filter-by-tags`` themselves?"
section bellow.

- Cleber.

>>
>> Looking at test tags
>> ====================
>>
>> Currently, there's no way to actually list the test tags from the
>> command line, alongside the test name themselves.  An RFE for fixing
>> this has been filed at https://trello.com/c/NXrbKEJC .
>>
>> Do users have to provide all the ``--filter-by-tags`` themselves?
>> =================================================================
>>
>> The test runner can certainly help here, getting system information
>> when the job starts, and feeding them to the filtering.  This is yet
>> another reason why coming up with a good set of guidelines for tagging
>> tests is important.
>>
>> In some ways, this can be seen similar to a dependency resolution
>> mechanism for tests, only that at this point it will not resolve the
>> requirements.  It will only filter out tests that can't (or shouldn't)
>> be loaded on the current system.
>>
>> Effectively, instead of many in-tests checks, and many SKIPs/CANCELs,
>> the system information can be loaded once, and the only relevant tests
>> will be part of the tests suite.
>>
>> A list of the tests that were filtered out from the job test suite can
>> certainly be a useful part of the job results.
>>
>> As in every RFC, feedback is extremely welcome!
> 

-- 
Cleber Rosa
[ Sr Software Engineer - Virtualization Team - Red Hat ]
[ Avocado Test Framework - avocado-framework.github.io ]
[  7ABB 96EB 8B46 B94D 5E0F  E9BB 657E 8D33 A5F2 09F3  ]

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