Re: [PATCH v3] docs: rust: Add rusttest info

[John Hubbard <jhubbard@nvidia.com>]

On 12/11/23 04:16, Dirk Behme wrote:
> Searching the Rust kernel documentation all existing Rust Make
> targets (rustavailable, rustfmt, rustfmtcheck, rustdoc and
> rust-analyzer) are explicitly documented with their Make syntax.
> While the Make target rusttest is mentioned two times in the
> existing documentation, it's Make syntax is not explicitly
> documented, yet. Add a test section to document this.
> 
> Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
> ---
> 
> v3: Add the comments from Benno and Miguel. Thanks!
> 
>   Documentation/rust/general-information.rst | 19 +++++++++++++++++++
>   1 file changed, 19 insertions(+)
> 
> diff --git a/Documentation/rust/general-information.rst b/Documentation/rust/general-information.rst
> index 081397827a7ea..016c7feb433ce 100644
> --- a/Documentation/rust/general-information.rst
> +++ b/Documentation/rust/general-information.rst
> @@ -77,3 +77,22 @@ configuration:
>   	#[cfg(CONFIG_X="y")]   // Enabled as a built-in (`y`)
>   	#[cfg(CONFIG_X="m")]   // Enabled as a module   (`m`)
>   	#[cfg(not(CONFIG_X))]  // Disabled
> +
> +Testing
> +-------
> +
> +To run the Rust tests, you can use the following make target::
> +
> +	make LLVM=1 rusttest

"make LLVM=1 <anything>" doesn't work for me, and therefore I suspect it
doesn't work for at least a few other people, as well.

Instead, I have to run "make CC=clang <anything>", which works just
fine.

The docs should consistently reflect this, yes?

> +
> +This requires the kernel .config and downloads external repos. It
> +runs the ``#[test]`` tests on the host (currently) and thus is fairly
> +limited in what these tests can test.
> +
> +Additonally, there are the tests that come from the examples in the
> +Rust documentation and get transformed into KUnit tests. These can be
> +run via KUnit. For example::
> +
> +	./tools/testing/kunit/kunit.py run --make_options LLVM=1 --arch x86_64 --kconfig_add CONFIG_RUST=y

Very helpful! Coming mostly from linux-mm, if someone says "run KUnit", I
have to pause and maybe go look it up, but having the command right in
front of me makes it all easy again. :)

Same comment about LLVM=1 vs. CC=clang, though.

> +
> +See the :doc:`KUnit documentation</dev-tools/kunit/index>` for the details how to use it.

Also good.


thanks,
-- 
John Hubbard
NVIDIA