Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Fri, 2 Sep 2022 15:38:28 +0200
From:   =?utf-8?Q?Micha=C5=82?= Winiarski <michal.winiarski@intel.com>
To:     Jani Nikula <jani.nikula@linux.intel.com>
CC:     Maxime Ripard <maxime@cerno.tech>,
        =?utf-8?B?TWHDrXJh?= Canal <mairacanal@riseup.net>,
        Isabella Basso <isabbasso@riseup.net>,
        <magalilemes00@gmail.com>, <tales.aparecida@gmail.com>,
        <mwen@igalia.com>, <andrealmeid@riseup.net>,
        <siqueirajordao@riseup.net>, Trevor Woerner <twoerner@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        David Airlie <airlied@linux.ie>,
        Javier Martinez Canillas <javierm@redhat.com>,
        David Gow <davidgow@google.com>, <brendanhiggins@google.com>,
        Arthur Grillo <arthur.grillo@usp.br>,
        =?utf-8?B?Sm9zw6kgRXhww7NzaXRv?= <jose.exposito89@gmail.com>,
        <linux-kernel@vger.kernel.org>, <dri-devel@lists.freedesktop.org>,
        <kunit-dev@googlegroups.com>
Subject: Re: [PATCH v2 2/2] drm/tests: Change "igt_" prefix to "test_drm_"
Message-ID: <20220902133828.ufwp6bgzd37yu6bv@nostramo.hardline.pl>
References: <20220901124210.591994-1-mairacanal@riseup.net>
 <20220901124210.591994-2-mairacanal@riseup.net>
 <20220901125530.b56s4zisnkfuigvc@houat>
 <04aeba53-793c-3196-3137-915f0640dc2a@riseup.net>
 <87h71qfbi9.fsf@intel.com>
 <20220902123400.5ljgc7z6zw34d64m@houat>
 <87mtbidj3b.fsf@intel.com>
Content-Type: text/plain; charset="utf-8"
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <87mtbidj3b.fsf@intel.com>
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?Q09nV0dTOUZJcDlaVU1sWkxPdG94M09pL1YwRmU1cU5vOEd1MDcyQ3ZZekVM?=
 =?utf-8?B?V1NRT0RCeXFyckN3emRQVXBvakJzdkJid29nYnI2TU5yR01kWE9lZ2VhaDFR?=
 =?utf-8?B?NHNNM0FMTVo2REV1NmFzOU9SRkJpMUZEVGdMS0hPRUpTTVpoSEJNVjNvWGRQ?=
 =?utf-8?B?clVHMXYzT3ZLSS81RnhNZXFRWjlDTU5mc1JNY0pHSFNkejVkWEJ3VExqRkxE?=
 =?utf-8?B?eGFtZ1hqMFNlOXl4SlFyc1NGZlNIZG53VUpKMzlxVlc0eXZORkhGemE5dmg0?=
 =?utf-8?B?TmtSVFA2STJoQzFNeUFmT3B5NHRzM1IvRnR3dG11NG5CamcyWWlwMzdJUzMx?=
 =?utf-8?B?SVdqRVNJOHAyN285cXh1Y3ZPRVFqeUdvN1dsYWRCb3hmRU1IYXQydUZaVyt4?=
 =?utf-8?B?RHJYWHh5akpDWVA1bDJ0K3JQN0Rtb3RoZzVObUZVeGEwK0xjWVJVV29CK05o?=
 =?utf-8?B?WW1jRlp1N04rREcrU2NrYVdPYVBUSTFwdnNtRWk0ZDNGdUJoWjNhZGp3Nm9o?=
 =?utf-8?B?Q1FBeWc3eFRTNFRxT2NlVFVTa0dNRmtzVGxuc2NrSVdNUlRkYVVldXJEWi9n?=
 =?utf-8?B?N1F4ZlF2bDhVSTNXb3BFTml5MkpQaHAwR21pMU9xVitrRjc1WDQwam4vRUJ1?=
 =?utf-8?B?RjluREtPQ0t3Ukl0NzV0Z1R1ZnNFUGJ3MzRzOVFYL2xpN1ZCMUdOTjhzK0Rq?=
 =?utf-8?B?U014ekxxMi9lbTlZTlBlb3puYkUxa0ZGaXdob1Bwa2pyNm43NW01YkNtd3dB?=
 =?utf-8?B?OTE3UHVKY1lXNm1zSnluWmNKODBjVEY4S2pqYUpHK3VqSGN5b1NkVTh4NnNt?=
 =?utf-8?B?U00yaDBsNElYekplTzgwV2U5VjlsWjk1VTd0QVhEeG1DeFlFSkhZTmYrSzdW?=
 =?utf-8?B?UUt5YW93RVVBY2FnOUZTQ1FGQU9ZYSs3WFdlV3lMcEZhTm52M2RQU2JpOEo1?=
 =?utf-8?B?OEhKVVBaNlNMSXJ1UHkwZkRtS1hxWXBmd0F5OUhnd1FQc1kwZ2NjRjlXRXpQ?=
 =?utf-8?B?Zkg2SHZHNmNGdyt3Y0ZMWUtXR0l4V3NvaHBQK1FacjI5MlR3SmNLTjhOZGwx?=
 =?utf-8?B?TmJyTHllcGdLNE0vMnd5Q25KeWVmMDdyb0ZzTEZYQVZMaytyNGw5VFpWbnhu?=
 =?utf-8?B?bTM0eUtKMkpwYkpwRkQ2MGdCTGZ0V1VUeGpRcytoaFQxaTNWamdXMUpUakdi?=
 =?utf-8?B?U2ZNTWJtbUFyb2ZSL0h0a2lyMnhDTjltS3BRV2ZwMjQ3VmdFb0pNY0ZzQVYw?=
 =?utf-8?B?YkpYZm9nN1pKbXB5SWZQNnhCMFMxR291T2xZa0VVSld4K3dJUlhsbWZadmsw?=
 =?utf-8?B?WWZ1cWxDM3F5c01iL1N6d0xFNFR6Y3dQN3QvU1NIRk1VaFV4QmVtalZEUWtP?=
 =?utf-8?B?T095aGNzamRZQnNKL1BCQjBKMlBmTkhMeWdGVllxUVJGRjJONjBtNmlYVW5j?=
 =?utf-8?B?SVA3ZHFkS25ORTgrWmIwaHMzOFhacEtHcW5pcEdzZjMzY2I1RjliTkZGMlRF?=
 =?utf-8?B?YmJ0K2FmMnJ3Nk84d21vQzJ4VFV0YzF2SlJtV1hJbWV0dWdZVkEzcURKM3dF?=
 =?utf-8?B?U0JuQkpaLzFVREFuT3c5VG5Xbm5WMFdFWGpjYm5jVTdOQ3Z3WjNkOStzYWc5?=
 =?utf-8?B?cDMvOWJGUU9lcEJkSitaNm9KNEI0Q3d3bFJ5ZDlYSytpUk5NcXhmVi9ZajlN?=
 =?utf-8?B?RGVBOXl3SWtsK0pVSVdwSkEzNE5mM3JGL3orbEh6cHZmUmtjKzRRSHdvTDdB?=
 =?utf-8?B?Q3Y3ZG1ITlUzTklXcUlkSnFmeFNPbFJOK3JXSllSTGFvVElxcUlBMU9NOWNx?=
 =?utf-8?B?U1A2cUYxYkdWcGxHMVh0MkhSZldCTlRGN3BhMWtZN1JsUjlqTjl1VWJvRXpv?=
 =?utf-8?B?Ri9yS3JsVEFJa3RZekxpclRmSjIranJRV3hodmN2Nlc4Z1pNS3JmN0tpdlJT?=
 =?utf-8?B?K1dpc3hCbm9tb0F4Ym5FcmhsU0RIZHNWSGs2WHB6OTEybE9IandJeVhtVW5o?=
 =?utf-8?B?TE84VWJoWVpEbjNCRFFLZnU4dTBJSUNXekxDbVFpNDJ2SnA2MDdSeU54QzRR?=
 =?utf-8?B?TzB3UW1XeUFjM200WHdWZ3h2R3ZGWXcya3grNnlDc0xuNUQvV2VEMFNJYmpF?=
 =?utf-8?B?Nno1L2wwYXEwU2krVVhKV1VYTFJHbkgwYjNKbk52aW1RRTZRSmF4dklLTFFF?=
 =?utf-8?B?OUE9PQ==?=
X-MS-Exchange-CrossTenant-Network-Message-Id: f4d3812f-c259-40a7-7e6b-08da8ce86f53
X-MS-Exchange-CrossTenant-AuthSource: DM4PR11MB5373.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 02 Sep 2022 13:38:35.5952
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: aJg5iCgqraHmjAlQKBXR14bbUsPTAuTtyfRYHDCVtwnt6qD6VDqPSCqhio6NJC5TPNP6DLatd5vZpENROWwe3Y9bmMggY1UCv6BrACLWwKw=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY8PR11MB7012
X-OriginatorOrg: intel.com
X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,
        DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED,
        SPF_HELO_PASS,SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=ham
        autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Fri, Sep 02, 2022 at 04:03:20PM +0300, Jani Nikula wrote:
> On Fri, 02 Sep 2022, Maxime Ripard <maxime@cerno.tech> wrote:
> > On Fri, Sep 02, 2022 at 11:04:14AM +0300, Jani Nikula wrote:
> >> On Thu, 01 Sep 2022, Maíra Canal <mairacanal@riseup.net> wrote:
> >> > Hi Maxime,
> >> >
> >> > On 9/1/22 09:55, Maxime Ripard wrote:
> >> >> Hi,
> >> >> 
> >> >> On Thu, Sep 01, 2022 at 09:42:10AM -0300, Maíra Canal wrote:
> >> >>> With the introduction of KUnit, IGT is no longer the only option to run
> >> >>> the DRM unit tests, as the tests can be run through kunit-tool or on
> >> >>> real hardware with CONFIG_KUNIT.
> >> >>>
> >> >>> Therefore, remove the "igt_" prefix from the tests and replace it with
> >> >>> the "test_drm_" prefix, making the tests' names independent from the tool
> >> >>> used.
> >> >>>
> >> >>> Signed-off-by: Maíra Canal <mairacanal@riseup.net>
> >> >>>
> >> >>> ---
> >> >>> v1 -> v2: https://lore.kernel.org/dri-devel/20220830211603.191734-1-mairacanal@riseup.net/
> >> >>> - Change "drm_" prefix to "test_drm_", as "drm_" can be a bit confusing (Jani Nikula).
> >> >> 
> >> >> I appreciate it's a bit of a bikeshed but I disagree with this. The
> >> >> majority of the kunit tests already out there start with the framework
> >> >> name, including *all* the examples in the kunit doc. Plus, it's fairly
> >> >> obvious that it's a test, kunit is only about running tests in the first
> >> >> place.
> >> >
> >> > Would it be better to keep it as "drm_"?
> >> 
> >> That's not "keeping". That's renaming igt to drm.
> >
> > Well, there's like half the tests that are prefixed with drm, the other
> > with igt, so it's both really
> >
> >> > Currently, I don't think it is appropriate to hold the "igt_" prefix, as
> >> > the tests are not IGT exclusive, but I don't have a strong opinion on
> >> > using the "drm_" or the "test_drm" prefixes.
> >> 
> >> I repeat my stance that "drm_" alone is confusing.
> >
> > What are you confusing it with?
> >
> >> For the reason alone that it pollutes the code tagging tools, mixing
> >> actual drm_ types and functions with unit test functions.
> >
> > I don't get it, I'm sorry. All these functions are static and not part
> > of any API, so I can't see how it would pollute a code tagging tool. Or
> > at least, not more than any driver does.
> >
> > And we're part of a larger project here, it's about consistency with the
> > rest of the ecosystem.
> 
> Okay, so I'm just going to explain what I mean, but say "whatever" right
> after and move on.
> 
> For example, drm_buddy_test.c includes drm_buddy.h so with the igt_ ->
> drm_ rename none of the test functions may clash with the drm_buddy_
> prefixed existing functions. Ditto for all tests similarly.
> 
> For example drm_buddy_alloc_range() as a name sounds like something that
> allocs a range, not something that tests range allocation. On the other
> hand, you have drm_buddy_alloc_blocks() which is actually a real
> drm_buddy function, not a test. What would you call a test that tests
> that? Here, we end up with names that are all prefixed drm_buddy and you
> won't know what's the actual function and what's the test unless you
> look it up.
> 
> I use code tagging that I can use for finding and completing
> e.g. functions. Currently I have the following completions, for
> igt_buddy_ and drm_buddy_, respectively:
> 
> Possible completions are:
> igt_buddy_alloc_limit 	igt_buddy_alloc_optimistic 	igt_buddy_alloc_pathological
> igt_buddy_alloc_pessimistic 	igt_buddy_alloc_range 	igt_buddy_alloc_smoke
> 
> Possible completions are:
> drm_buddy_alloc_blocks 	drm_buddy_block 	drm_buddy_block_is_allocated 	drm_buddy_block_is_free
> drm_buddy_block_is_split 	drm_buddy_block_offset 	drm_buddy_block_order 	drm_buddy_block_print
> drm_buddy_block_size 	drm_buddy_block_state 	drm_buddy_block_trim 	drm_buddy_fini
> drm_buddy_free_block 	drm_buddy_free_list 	drm_buddy_init 	drm_buddy_init_test
> drm_buddy_module_exit 	drm_buddy_module_init 	drm_buddy_print
> 
> With the patch at hand, they'll all be lumped under drm_buddy_
> completions, and some of them will be actual drm buddy functions and
> some not.
> 
> I just find it a very odd convention to name the tests in a way that's
> indistinguishable from the real things. Even *within* drm_buddy_test.c
> where you read the test code. Because currently you do have calls to
> igt_buddy_ prefixed functions from other igt_buddy_ prefixed functions,
> along with the drm_buddy_ prefixed calls. I think it's just going to be
> a mess.
> 
> /rant
> 
> Whatever. Moving on.

KUnit docs [1] state:
https://docs.kernel.org/dev-tools/kunit/style.html#test-cases
"As tests are themselves functions, their names cannot conflict with other
C identifiers in the kernel. This may require some creative naming."
And give examples of names. But this should be local to individual test suite -
as long as the test is readable, and the name describes what it is testing, we
should be fine. We don't even need to pass drm_* prefix, as this convention is
expected for test suites, not test cases [2].

Having said that - I do believe that igt_* prefix don't belong here (which is
why I'm progressively trying to get rid of in the patches that refactor some of
the tests).
I agree with Jani - can we take it on a case-by-case basis?
If the test name is too similar to the function that it is testing, we could go
with one of the following (taking igt_buddy_alloc_limit as example):
drm_buddy_test_alloc_limit
test_drm_buddy_alloc_limit
buddy_test_alloc_limit
test_buddy_alloc_limit

And either of those is fine in my opinion (I'd personally go with
test_buddy_alloc_limit in this case).
We don't really need a DRM-wide (or worse, kernel wide) convention for test case
names (it's only really needed for test suites).

[1] https://docs.kernel.org/dev-tools/kunit/style.html#test-cases
[2] https://docs.kernel.org/dev-tools/kunit/style.html#suites

-Michał

> 
> 
> BR,
> Jani.
> 
> 
> -- 
> Jani Nikula, Intel Open Source Graphics Center