Re: [PATCH v3 05/11] of: Add a KUnit test for overlays and test managed APIs

From: Stephen Boyd <sboyd@kernel.org>
To: Daniel Latypov <dlatypov@google.com>
Cc: Michael Turquette <mturquette@baylibre.com>,
	linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org,
	patches@lists.linux.dev,
	Brendan Higgins <brendan.higgins@linux.dev>,
	David Gow <davidgow@google.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Rafael J . Wysocki <rafael@kernel.org>,
	Rob Herring <robh+dt@kernel.org>,
	Frank Rowand <frowand.list@gmail.com>,
	Christian Marangi <ansuelsmth@gmail.com>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	devicetree@vger.kernel.org, linux-kselftest@vger.kernel.org,
	kunit-dev@googlegroups.com, Maxime Ripard <maxime@cerno.tech>
Subject: Re: [PATCH v3 05/11] of: Add a KUnit test for overlays and test managed APIs
Date: Wed, 12 Apr 2023 17:26:02 -0700	[thread overview]
Message-ID: <eaf237baf3a0bfd5bf4c7e97e32f9261.sboyd@kernel.org> (raw)
In-Reply-To: <CAGS_qxryWVOT9cBtKk28=NupbLP6_AiCj0P3np2GpMVKkyQOLg@mail.gmail.com>

Quoting Daniel Latypov (2023-04-12 17:04:26)
> On Mon, Mar 27, 2023 at 3:22 PM Stephen Boyd <sboyd@kernel.org> wrote:
> > +/* Test that of_overlay_apply_kunit() cleans up after the test is finished */
> > +static void of_overlay_apply_kunit_cleanup(struct kunit *test)
> > +{
> > +       struct device *dev;
> > +       struct device_node *np;
> > +
> > +       KUNIT_ASSERT_EQ(test, 0,
> > +                       of_overlay_apply_kunit(test, kunit_overlay_test));
> > +
> > +       np = of_find_node_by_name(NULL, kunit_node_name);
> > +       of_node_put(np); /* Not derefing 'np' after this */
> > +       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, np);
> > +
> > +       dev = bus_find_device(&platform_bus_type, NULL, np, bus_match_np);
> > +       put_device(dev); /* Not derefing 'device' after this */
> > +       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dev);
> > +
> > +       /* Remove overlay */
> > +       kunit_cleanup(test);
> 
> Note: this cleans up *all* resources associated with `test`.
> Right now, it's probably fine, but this probably isn't the safest approach.
> 
> Notably, two of the new/upcoming API changes rely on resource,
> kunit/static_stub.h and kunit_add_action() [1].
> Calling kunit_cleanup() undoes all the stubs and immediately triggers
> all the actions.
> 
> Perhaps you can create your own local `struct kunit` like in [2]
> E.g.
> 
> struct kunit subtest; // not sure what to call this...
> 
> kunit_init_test(&subtest, "fake test", NULL);
> /* use subtest */
> kunit_cleanup(&subtest);

Thanks for the pointers. I can change this to be a fake sub-test as
that's the intention here. I was mostly following what
kunit_resource_test_static() was doing, which was calling
kunit_cleanup() on the existing test that's passed in.