| Message ID | 20241101064505.3820737-1-davidgow@google.com |
|---|---|
| Headers | show |
| Series | rust: kunit: Support KUnit tests with a user-space like syntax | expand |
On Fri, Nov 01, 2024 at 02:45:02PM +0800, David Gow wrote: [...] > +/// ``` > +/// // Import our mock naming it as the real module. > +/// #[cfg(CONFIG_KUNIT)] > +/// use bindings_mock_example as bindings; > +/// > +/// // This module mocks `bindings`. > +/// mod bindings_mock_example { > +/// use kernel::kunit::in_kunit_test; > +/// use kernel::bindings::u64_; > +/// > +/// // Make the other binding functions available. > +/// pub(crate) use kernel::bindings::*; > +/// > +/// // Mock `ktime_get_boot_fast_ns` to return a well-known value when running a KUnit test. > +/// pub(crate) unsafe fn ktime_get_boot_fast_ns() -> u64_ { Clippy complains this `unsafe` pub function doesn't have a "# Safety" section. Actually this function is not necessarily to be `unsafe`. > +/// if in_kunit_test() { > +/// 1234 > +/// } else { > +/// unsafe { kernel::bindings::ktime_get_boot_fast_ns() } Need safety comments here, > +/// } > +/// } > +/// } > +/// > +/// // This is the function we want to test. Since `bindings` has been mocked, we can use its > +/// // functions seamlessly. > +/// fn get_boot_ns() -> u64 { > +/// unsafe { bindings::ktime_get_boot_fast_ns() } and here. If you make ktime_get_boot_fast_ns() safe, then no unsafe block is needed here. Regards, Boqun > +/// } > +/// > +/// let time = get_boot_ns(); > +/// assert_eq!(time, 1234); > +/// ``` > +pub fn in_kunit_test() -> bool { > + // SAFETY: kunit_get_current_test() is always safe to call from C (it has fallbacks for > + // when KUnit is not enabled), and we're only comparing the result to NULL. > + unsafe { !bindings::kunit_get_current_test().is_null() } > +} > + > #[kunit_tests(rust_kernel_kunit)] > mod tests { > + use super::*; > + > #[test] > fn rust_test_kunit_example_test() { > assert_eq!(1 + 1, 2); > } > + > + #[test] > + fn rust_test_kunit_in_kunit_test() { > + let in_kunit = in_kunit_test(); > + assert!(in_kunit); > + } > } > -- > 2.47.0.199.ga7371fff76-goog >
On Sat, 2 Nov 2024 at 01:47, Boqun Feng <boqun.feng@gmail.com> wrote: > > On Fri, Nov 01, 2024 at 02:45:00PM +0800, David Gow wrote: > > From: José Expósito <jose.exposito89@gmail.com> > > > > 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 <jose.exposito89@gmail.com> > > Co-developed-by: Matt Gilbride <mattgilbride@google.com> > > Signed-off-by: Matt Gilbride <mattgilbride@google.com> > > Co-developed-by: David Gow <davidgow@google.com> > > Signed-off-by: David Gow <davidgow@google.com> > > --- > > > > Changes since v3: > > https://lore.kernel.org/linux-kselftest/20241030045719.3085147-4-davidgow@google.com/ > > - The kunit_unsafe_test_suite!() macro now panic!s if the suite name is > > too long, triggering a compile error. (Thanks, Alice!) > > > > Changes since v2: > > https://lore.kernel.org/linux-kselftest/20241029092422.2884505-2-davidgow@google.com/ > > - The kunit_unsafe_test_suite!() macro will truncate the name of the > > suite if it is too long. (Thanks Alice!) > > - We no longer needlessly use UnsafeCell<> in > > kunit_unsafe_test_suite!(). (Thanks Alice!) > > > > Changes since v1: > > https://lore.kernel.org/lkml/20230720-rustbind-v1-1-c80db349e3b5@google.com/ > > - 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 | 112 +++++++++++++++++++++++++++++++++++++++++++ > > rust/kernel/lib.rs | 1 + > > 2 files changed, 113 insertions(+) > > > > diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs > > index 824da0e9738a..85bc1faff0d5 100644 > > --- a/rust/kernel/kunit.rs > > +++ b/rust/kernel/kunit.rs > > @@ -161,3 +161,115 @@ 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: &'static kernel::str::CStr, run_case: unsafe extern "C" fn(*mut kernel::bindings::kunit)) -> kernel::bindings::kunit_case { > > + kernel::bindings::kunit_case { > > + run_case: Some(run_case), > > + name: name.as_char_ptr(), > > + attr: kernel::bindings::kunit_attributes { > > + speed: kernel::bindings::kunit_speed_KUNIT_SPEED_NORMAL, > > + }, > > + generate_params: None, > > + status: kernel::bindings::kunit_status_KUNIT_SUCCESS, > > + module_name: core::ptr::null_mut(), > > + log: core::ptr::null_mut(), > > + } > > +} > > + > > +/// Represents the NULL test case delimiter. > > +/// > > +/// The `kunit_unsafe_test_suite!` macro expects a NULL-terminated list of test cases. This > > +/// function retuns such a delimiter. > > +const fn kunit_case_null() -> kernel::bindings::kunit_case { > > + kernel::bindings::kunit_case { > > + run_case: None, > > + name: core::ptr::null_mut(), > > + generate_params: None, > > + attr: kernel::bindings::kunit_attributes { > > + speed: kernel::bindings::kunit_speed_KUNIT_SPEED_NORMAL, > > + }, > > + status: kernel::bindings::kunit_status_KUNIT_SUCCESS, > > + module_name: core::ptr::null_mut(), > > + log: core::ptr::null_mut(), > > + } > > +} > > + > > + > > +/// 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]; > > + > > + if name_u8.len() > 255 { > > + panic!(concat!("The test suite name `", core::stringify!($name), "` exceeds the maximum length of 255 bytes.")); > > + } > > + > > + let mut i = 0; > > + while i < name_u8.len() { > > + ret[i] = name_u8[i] as i8; > > + i += 1; > > + } > > + > > + ret > > + }; > > + > > + static mut KUNIT_TEST_SUITE: $crate::bindings::kunit_suite = > > + $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 { core::ptr::addr_of_mut!(KUNIT_TEST_SUITE) }; > > FYI, `addr_of` and `addr_of_mut` is safe now on statics since 1.82: > > https://blog.rust-lang.org/2024/10/17/Rust-1.82.0.html#safely-addressing-unsafe-statics > > We need a `#[allow(unused_unsafe)]` here to avoid the unused unsafe > warning. > I've not been able to work out how to fix this: adding "#![allow(unused_unsafe)]" to the unsafe block here triggers another error: ERROR:root:error[E0658]: attributes on expressions are experimental Is there somewhere else we can put the attribute to support this without having to either disable the warning, or use the experimental feature globally? -- David
On Sat, Nov 9, 2024 at 9:18 AM David Gow <davidgow@google.com> wrote: > > Is there somewhere else we can put the attribute to support this > without having to either disable the warning, or use the experimental > feature globally? Yeah, on the item, e.g. https://godbolt.org/z/oo8osadn4: const _: () = { static mut X: i32 = 42; #[allow(unused_unsafe)] static mut S: *const i32 = unsafe { core::ptr::addr_of_mut!(X) }; }; Cheers, Miguel
This series was originally written by José Expósito, and has been modified and updated by Matt Gilbride and myself. The original version can be found here: https://github.com/Rust-for-Linux/linux/pull/950 Add support for writing KUnit tests in Rust. While Rust doctests are already converted to KUnit tests and run, they're really better suited for examples, rather than as first-class unit tests. This series implements a series of direct Rust bindings for KUnit tests, as well as a new macro which allows KUnit tests to be written using a close variant of normal Rust unit test syntax. The only change required is replacing '#[cfg(test)]' with '#[kunit_tests(kunit_test_suite_name)]' An example test would look like: #[kunit_tests(rust_kernel_hid_driver)] mod tests { use super::*; use crate::{c_str, driver, hid, prelude::*}; use core::ptr; struct SimpleTestDriver; impl Driver for SimpleTestDriver { type Data = (); } #[test] fn rust_test_hid_driver_adapter() { let mut hid = bindings::hid_driver::default(); let name = c_str!("SimpleTestDriver"); static MODULE: ThisModule = unsafe { ThisModule::from_ptr(ptr::null_mut()) }; let res = unsafe { <hid::Adapter<SimpleTestDriver> as driver::DriverOps>::register(&mut hid, name, &MODULE) }; assert_eq!(res, Err(ENODEV)); // The mock returns -19 } } Please give this a go, and make sure I haven't broken it! There's almost certainly a lot of improvements which can be made -- and there's a fair case to be made for replacing some of this with generated C code which can use the C macros -- but this is hopefully an adequate implementation for now, and the interface can (with luck) remain the same even if the implementation changes. A few small notable missing features: - Attributes (like the speed of a test) are hardcoded to the default value. - Similarly, the module name attribute is hardcoded to NULL. In C, we use the KBUILD_MODNAME macro, but I couldn't find a way to use this from Rust which wasn't more ugly than just disabling it. - Assertions are not automatically rewritten to use KUnit assertions. --- Changes since v3: https://lore.kernel.org/linux-kselftest/20241030045719.3085147-2-davidgow@google.com/T/ - The kunit_unsafe_test_suite!() macro now panic!s if the suite name is too long, triggering a compile error. (Thanks, Alice!) - The #[kunit_tests()] macro now preserves span information, so errors can be better reported. (Thanks, Boqun!) - The example tests have been updated to no longer use assert_eq!() with a constant bool argument (which triggered a clippy warning now we have the span info). Changes since v2: https://lore.kernel.org/linux-kselftest/20241029092422.2884505-1-davidgow@google.com/T/ - Include missing rust/macros/kunit.rs file from v2. (Thanks Boqun!) - The kunit_unsafe_test_suite!() macro will truncate the name of the suite if it is too long. (Thanks Alice!) - The proc macro now emits an error if the suite name is too long. - We no longer needlessly use UnsafeCell<> in kunit_unsafe_test_suite!(). (Thanks Alice!) Changes since v1: https://lore.kernel.org/lkml/20230720-rustbind-v1-0-c80db349e3b5@google.com/T/ - Rebase on top of the latest rust-next (commit 718c4069896c) - Make kunit_case a const fn, rather than a macro (Thanks Boqun) - As a result, the null terminator is now created with kernel::kunit::kunit_case_null() - Use the C kunit_get_current_test() function to implement in_kunit_test(), rather than re-implementing it (less efficiently) ourselves. Changes since the GitHub PR: - Rebased on top of kselftest/kunit - Add const_mut_refs feature This may conflict with https://lore.kernel.org/lkml/20230503090708.2524310-6-nmi@metaspace.dk/ - Add rust/macros/kunit.rs to the KUnit MAINTAINERS entry --- José Expósito (3): rust: kunit: add KUnit case and suite macros rust: macros: add macro to easily run KUnit tests rust: kunit: allow to know if we are in a test MAINTAINERS | 1 + rust/kernel/kunit.rs | 194 +++++++++++++++++++++++++++++++++++++++++++ rust/kernel/lib.rs | 1 + rust/macros/kunit.rs | 168 +++++++++++++++++++++++++++++++++++++ rust/macros/lib.rs | 29 +++++++ 5 files changed, 393 insertions(+) create mode 100644 rust/macros/kunit.rs