Re: [PATCH 4/7] rust: str: convert `rusttest` tests into KUnit

[Tamir Duberstein]

On Sun, May 4, 2025 at 2:31 PM Miguel Ojeda
<miguel.ojeda.sandonis@xxxxxxxxx> wrote:
>
> On Sun, May 4, 2025 at 7:31 PM Tamir Duberstein <tamird@xxxxxxxxx> wrote:
> >
> > Is that true? The build host is often easier to work with. There's a
> > number of host tests on the C side that exist precisely for this
> > reason.
>
> Even for tests that could run in the host (pure functions), if you
> test in the host, then you are not testing the actual kernel code, in
> the sense of same compile flags, target, etc.
>
> Moreover, you have UML, which gives you access to other APIs.
>
> As for "easier to work with", I am not sure what you mean -- KUnit
> does not really require anything special w.r.t. building the kernel
> normally. In a way, these restricted host tests actually are an extra
> hassle, in that you have to deal with yet another test environment and
> special restrictions.

All good points.

> But which host tests are you referring to?

One example is https://github.com/torvalds/linux/blob/59c9ab3e8cc7f56cd65608f6e938b5ae96eb9cd2/tools/testing/radix-tree/xarray.c.

It might be that these are necessary because the xarray tests don't
use kunit, and so are pretty inconvenient to run. As you might have
guessed, I discovered these host tests when my patch porting the
xarray tests to kunit broke the host-side build :(