Re: [PATCH v6 01/18] kunit: test: add KUnit test runner core

From: Luis Chamberlain <mcgrof@kernel.org>
To: Brendan Higgins <brendanhiggins@google.com>
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Subject: Re: [PATCH v6 01/18] kunit: test: add KUnit test runner core
Date: Fri, 5 Jul 2019 20:15:05 +0000	[thread overview]
Message-ID: <20190705201505.GA19023@42.do-not-panic.com> (raw)
In-Reply-To: <20190704003615.204860-2-brendanhiggins@google.com>

On Wed, Jul 03, 2019 at 05:35:58PM -0700, Brendan Higgins wrote:
> Add core facilities for defining unit tests; this provides a common way
> to define test cases, functions that execute code which is under test
> and determine whether the code under test behaves as expected; this also
> provides a way to group together related test cases in test suites (here
> we call them test_modules).
> 
> Just define test cases and how to execute them for now; setting
> expectations on code will be defined later.
> 
> Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Reviewed-by: Logan Gunthorpe <logang@deltatee.com>

Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>

But a nitpick below, I think that can be fixed later with a follow up
patch.

> +/**
> + * struct kunit - represents a running instance of a test.
> + * @priv: for user to store arbitrary data. Commonly used to pass data created
> + * in the init function (see &struct kunit_suite).
> + *
> + * Used to store information about the current context under which the test is
> + * running. Most of this data is private and should only be accessed indirectly
> + * via public functions; the one exception is @priv which can be used by the
> + * test writer to store arbitrary data.
> + *
> + * A brief note on locking:
> + *
> + * First off, we need to lock because in certain cases a user may want to use an
> + * expectation in a thread other than the thread that the test case is running
> + * in.

This as a prefix to the struct without a lock seems odd. It would be
clearer I think if you'd explain here what locking mechanism we decided
to use and why it suffices today.

> +/**
> + * suite_test() - used to register a &struct kunit_suite with KUnit.

You mean kunit_test_suite()?

> + * @suite: a statically allocated &struct kunit_suite.
> + *
> + * Registers @suite with the test framework. See &struct kunit_suite for more
> + * information.
> + *
> + * NOTE: Currently KUnit tests are all run as late_initcalls; this means that
> + * they cannot test anything where tests must run at a different init phase. One
> + * significant restriction resulting from this is that KUnit cannot reliably
> + * test anything that is initialize in the late_init phase.
                            initialize prior to the late init phase.

That is, this is useless to test things running early.

> + *
> + * TODO(brendanhiggins@google.com): Don't run all KUnit tests as late_initcalls.
> + * I have some future work planned to dispatch all KUnit tests from the same
> + * place, and at the very least to do so after everything else is definitely
> + * initialized.

TODOs are odd to be adding to documentation, this is just not common
place practice. The NOTE should suffice for you.

  Luis
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