Message-ID: <39a7b489-4856-8dc1-d0a6-f27d0c1324a2@gmail.com>
Date:   Mon, 13 Mar 2023 15:59:51 +0200
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Subject: Re: [PATCH v3 2/6] iio: light: Add gain-time-scale helpers
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To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc:     Jonathan Cameron <jic23@kernel.org>,
        Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Shreeya Patel <shreeya.patel@collabora.com>,
        Paul Gazzillo <paul@pgazz.com>,
        Dmitry Osipenko <dmitry.osipenko@collabora.com>,
        Zhigang Shi <Zhigang.Shi@liteon.com>,
        linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org
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 <31d8bc33-eabe-9084-71c3-7d1e29f51863@gmail.com>
 <ZA8lNBPCB4BNnfUq@smile.fi.intel.com>
From:   Matti Vaittinen <mazziesaccount@gmail.com>
In-Reply-To: <ZA8lNBPCB4BNnfUq@smile.fi.intel.com>
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On 3/13/23 15:29, Andy Shevchenko wrote:
> On Mon, Mar 13, 2023 at 03:11:52PM +0200, Matti Vaittinen wrote:
>> On 3/13/23 14:40, Andy Shevchenko wrote:
>>> On Sun, Mar 12, 2023 at 05:08:48PM +0000, Jonathan Cameron wrote:
>>>> On Sun, 12 Mar 2023 17:06:38 +0000
>>>> Jonathan Cameron <jic23@kernel.org> wrote:
> 
> ...
> 
>>>> Ah. I forgot the tests that don't have a device so can't use devm.
>>>
>>> Why not? I have seen, IIRC, test cases inside the kernel that fakes the device
>>> for that.
>>
>> I'd appreciated any pointer for such an example if you have one at hand. (I
>> can do the digging if you don't though!)
>>
>> I am not a fan of unit tests. They add huge amount of inertia to
>> development, and in worst case, they stop people from contributing where
>> improving a feature requires test code modification(s). And harder the test
>> code is to understand, worse the unwanted side-effects. Also, harder the
>> test code is to read, more time and effort it requires to analyze a test
>> failure... Hence, I am _very_ conservative what comes to adding size of test
>> code with anything that is not strictly required.
>>
>> After that being said, unit tests are a great tool when carefully used - and
>> I assume/hope stubbing a device for devm_ tests does not add much extra...
>> But let me see if I can find an example :)
> 
> drivers/gpu/drm/tests/drm_managed_test.c ?
> 
> (somewhere underneath:
> 
>   ret = platform_driver_register(&fake_platform_driver);
> 
> which suggests... what exactly? :-)
> 

Thanks!

--Matti

-- 
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

~~ When things go utterly wrong vim users can always type :help! ~~