On Tue, 29 Oct 2024 at 20:08, Alice Ryhl <[email protected]> wrote: > > On Tue, Oct 29, 2024 at 10:24 AM David Gow <[email protected]> wrote: > > > > From: José Expósito <[email protected]> > > > > Add a couple of Rust const functions and macros to allow to develop > > KUnit tests without relying on generated C code: > > > > - The `kunit_unsafe_test_suite!` Rust macro is similar to the > > `kunit_test_suite` C macro. It requires a NULL-terminated array of > > test cases (see below). > > - The `kunit_case` Rust function is similar to the `KUNIT_CASE` C macro. > > It generates as case from the name and function. > > - The `kunit_case_null` Rust function generates a NULL test case, which > > is to be used as delimiter in `kunit_test_suite!`. > > > > While these functions and macros can be used on their own, a future > > patch will introduce another macro to create KUnit tests using a > > user-space like syntax. > > > > Signed-off-by: José Expósito <[email protected]> > > Co-developed-by: Matt Gilbride <[email protected]> > > Signed-off-by: Matt Gilbride <[email protected]> > > Co-developed-by: David Gow <[email protected]> > > Signed-off-by: David Gow <[email protected]> > > --- > > > > Changes since v1: > > https://lore.kernel.org/lkml/[email protected]/ > > - Rebase on top of rust-next > > - As a result, KUnit attributes are new set. These are hardcoded to the > > defaults of "normal" speed and no module name. > > - Split the kunit_case!() macro into two const functions, kunit_case() > > and kunit_case_null() (for the NULL terminator). > > > > --- > > rust/kernel/kunit.rs | 108 +++++++++++++++++++++++++++++++++++++++++++ > > rust/kernel/lib.rs | 1 + > > 2 files changed, 109 insertions(+) > > > > diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs > > index 824da0e9738a..fc2d259db458 100644 > > --- a/rust/kernel/kunit.rs > > +++ b/rust/kernel/kunit.rs > > @@ -161,3 +161,111 @@ macro_rules! kunit_assert_eq { > > $crate::kunit_assert!($name, $file, $diff, $left == $right); > > }}; > > } > > + > > +/// Represents an individual test case. > > +/// > > +/// The test case should have the signature > > +/// `unsafe extern "C" fn test_case(test: *mut crate::bindings::kunit)`. > > +/// > > +/// The `kunit_unsafe_test_suite!` macro expects a NULL-terminated list of > > test cases. > > +/// Use `kunit_case_null` to generate such a delimeter. > > +const fn kunit_case(name: &kernel::str::CStr, run_case: unsafe extern "C" > > fn(*mut kernel::bindings::kunit)) -> kernel::bindings::kunit_case { > > This should probably say `name: &'static CStr` to require that the > name lives forever.
Fixed in v3, thanks.
> > +/// Registers a KUnit test suite.
> > +///
> > +/// # Safety
> > +///
> > +/// `test_cases` must be a NULL terminated array of test cases.
> > +///
> > +/// # Examples
> > +///
> > +/// ```ignore
> > +/// unsafe extern "C" fn test_fn(_test: *mut crate::bindings::kunit) {
> > +/// let actual = 1 + 1;
> > +/// let expected = 2;
> > +/// assert_eq!(actual, expected);
> > +/// }
> > +///
> > +/// static mut KUNIT_TEST_CASE: crate::bindings::kunit_case =
> > crate::kunit_case(name, test_fn);
> > +/// static mut KUNIT_NULL_CASE: crate::bindings::kunit_case =
> > crate::kunit_case_null();
> > +/// static mut KUNIT_TEST_CASES: &mut[crate::bindings::kunit_case] =
> > unsafe {
> > +/// &mut[KUNIT_TEST_CASE, KUNIT_NULL_CASE]
> > +/// };
> > +/// crate::kunit_unsafe_test_suite!(suite_name, KUNIT_TEST_CASES);
> > +/// ```
> > +#[macro_export]
> > +macro_rules! kunit_unsafe_test_suite {
> > + ($name:ident, $test_cases:ident) => {
> > + const _: () = {
> > + static KUNIT_TEST_SUITE_NAME: [i8; 256] = {
> > + let name_u8 = core::stringify!($name).as_bytes();
> > + let mut ret = [0; 256];
> > +
> > + let mut i = 0;
> > + while i < name_u8.len() {
> > + ret[i] = name_u8[i] as i8;
> > + i += 1;
> > + }
>
> I assume the name must be zero-terminated? If so, you probably need to
> enforce that somehow, e.g. by failing if `name_u8` is longer than 255
> bytes.
Nice catch. I'm not sure how to nicely throw a compile time error in
this function, so I'm truncating it here and doing a compile error in
the macro in patch #2. This isn't ideal, but seems to work.
> > +
> > + static mut KUNIT_TEST_SUITE:
> > core::cell::UnsafeCell<$crate::bindings::kunit_suite> =
>
> You don't actually need UnsafeCell here since it's already `static mut`.
>
Thanks, this works.
> > + core::cell::UnsafeCell::new($crate::bindings::kunit_suite {
> > + name: KUNIT_TEST_SUITE_NAME,
> > + // SAFETY: User is expected to pass a correct
> > `test_cases`, hence this macro
> > + // named 'unsafe'.
> > + test_cases: unsafe { $test_cases.as_mut_ptr() },
> > + suite_init: None,
> > + suite_exit: None,
> > + init: None,
> > + exit: None,
> > + attr: $crate::bindings::kunit_attributes {
> > + speed:
> > $crate::bindings::kunit_speed_KUNIT_SPEED_NORMAL,
> > + },
> > + status_comment: [0; 256usize],
> > + debugfs: core::ptr::null_mut(),
> > + log: core::ptr::null_mut(),
> > + suite_init_err: 0,
> > + is_init: false,
> > + });
> > +
> > + #[used]
> > + #[link_section = ".kunit_test_suites"]
> > + static mut KUNIT_TEST_SUITE_ENTRY: *const
> > $crate::bindings::kunit_suite =
> > + // SAFETY: `KUNIT_TEST_SUITE` is static.
> > + unsafe { KUNIT_TEST_SUITE.get() };
>
> If you change `KUNIT_TEST_SUITE` to not be an UnsafeCell, then you'll
> want to do `core::ptr::addr_of_mut!(KUNIT_TEST_SUITE` instead.
>
> > diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
> > index b62451f64f6e..d662aa37070f 100644
> > --- a/rust/kernel/lib.rs
> > +++ b/rust/kernel/lib.rs
> > @@ -18,6 +18,7 @@
> > #![feature(inline_const)]
> > #![feature(lint_reasons)]
> > #![feature(unsize)]
> > +#![feature(const_mut_refs)]
>
> Is this still needed with the above changes?
>
Yes, this seems to still be needed for the kunit_unsafe_test_suite!() macro.
Thanks,
-- David
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