Currently, return values of KUnit `#[test]` functions are ignored.
Thus introduce support for `-> Result` functions by checking their returned values.
At the same time, require that test functions return `()` or `Result<T, E>`, which should avoid mistakes, especially with non-`#[must_use]` types. Other types can be supported in the future if needed.
With this, a failing test like:
#[test] fn my_test() -> Result { f()?; Ok(()) }
will output:
[ 3.744214] KTAP version 1 [ 3.744287] # Subtest: my_test_suite [ 3.744378] # speed: normal [ 3.744399] 1..1 [ 3.745817] # my_test: ASSERTION FAILED at rust/kernel/lib.rs:321 [ 3.745817] Expected is_test_result_ok(my_test()) to be true, but is false [ 3.747152] # my_test.speed: normal [ 3.747199] not ok 1 my_test [ 3.747345] not ok 4 my_test_suite
Signed-off-by: Miguel Ojeda ojeda@kernel.org --- rust/kernel/kunit.rs | 25 +++++++++++++++++++++++++ rust/macros/kunit.rs | 3 ++- 2 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs index 2659895d4c5d..f43e3ed460c2 100644 --- a/rust/kernel/kunit.rs +++ b/rust/kernel/kunit.rs @@ -164,6 +164,31 @@ macro_rules! kunit_assert_eq { }}; }
+trait TestResult { + fn is_test_result_ok(&self) -> bool; +} + +impl TestResult for () { + fn is_test_result_ok(&self) -> bool { + true + } +} + +impl<T, E> TestResult for Result<T, E> { + fn is_test_result_ok(&self) -> bool { + self.is_ok() + } +} + +/// Returns whether a test result is to be considered OK. +/// +/// This will be `assert!`ed from the generated tests. +#[doc(hidden)] +#[expect(private_bounds)] +pub fn is_test_result_ok(t: impl TestResult) -> bool { + t.is_test_result_ok() +} + /// Represents an individual test case. /// /// The [`kunit_unsafe_test_suite!`] macro expects a NULL-terminated list of valid test cases. diff --git a/rust/macros/kunit.rs b/rust/macros/kunit.rs index eb4f2afdbe43..9681775d160a 100644 --- a/rust/macros/kunit.rs +++ b/rust/macros/kunit.rs @@ -105,8 +105,9 @@ pub(crate) fn kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream { let path = crate::helpers::file(); for test in &tests { let kunit_wrapper_fn_name = format!("kunit_rust_wrapper_{}", test); + // An extra `use` is used here to reduce the length of the message. let kunit_wrapper = format!( - "unsafe extern "C" fn {}(_test: *mut kernel::bindings::kunit) {{ {}(); }}", + "unsafe extern "C" fn {}(_test: *mut kernel::bindings::kunit) {{ use kernel::kunit::is_test_result_ok; assert!(is_test_result_ok({}())); }}", kunit_wrapper_fn_name, test ); writeln!(kunit_macros, "{kunit_wrapper}").unwrap();