[PATCH 1/3] rust: kunit: add KUnit case and suite macros

David Gow
2023-07-20T06:41:03Z

From: José Expósito <jose.exposito89@gmail.com>

Add a couple of Rust 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.
- The `kunit_case!` Rust macro is similar to the `KUNIT_CASE` C macro.
It can be used with parameters to generate a test case or without
parameters to be used as delimiter in `kunit_test_suite!`.

While these macros can be used on their own, a future patch will
introduce another macro to create KUnit tests using a user-space like
syntax.

Co-developed-by: David Gow <davidgow@google.com>
Signed-off-by: David Gow <davidgow@google.com>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
---
rust/kernel/kunit.rs | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++++
rust/kernel/lib.rs | 1 +
2 files changed, 93 insertions(+)

diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs
index 722655b2d62d..4cffc71e463b 100644
--- a/rust/kernel/kunit.rs
+++ b/rust/kernel/kunit.rs
@@ -161,3 +161,95 @@ 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. This macro
+/// can be invoked without parameters to generate the delimiter.
+#[macro_export]
+macro_rules! kunit_case {
+ () => {
+ $crate::bindings::kunit_case {
+ run_case: None,
+ name: core::ptr::null_mut(),
+ generate_params: None,
+ status: $crate::bindings::kunit_status_KUNIT_SUCCESS,
+ log: core::ptr::null_mut(),
+ }
+ };
+ ($name:ident, $run_case:ident) => {
+ $crate::bindings::kunit_case {
+ run_case: Some($run_case),
+ name: $crate::c_str!(core::stringify!($name)).as_char_ptr(),
+ generate_params: None,
+ status: $crate::bindings::kunit_status_KUNIT_SUCCESS,
+ log: core::ptr::null_mut(),
+ }
+ };
+}
+
+/// Registers a KUnit test suite.
+///
+/// # Safety
+///
+/// `test_cases` must be a NULL terminated array of test cases.
+///
+/// # Examples
+///
+/// ```ignore
+/// unsafe extern "C" fn test_fn(_test: *mut crate::bindings::kunit) {
+/// let actual = 1 + 1;
+/// let expected = 2;
+/// assert_eq!(actual, expected);
+/// }
+///
+/// static mut KUNIT_TEST_CASE: crate::bindings::kunit_case = crate::kunit_case!(name, test_fn);
+/// static mut KUNIT_NULL_CASE: crate::bindings::kunit_case = crate::kunit_case!();
+/// static mut KUNIT_TEST_CASES: &mut[crate::bindings::kunit_case] = unsafe {
+/// &mut[KUNIT_TEST_CASE, KUNIT_NULL_CASE]
+/// };
+/// crate::kunit_unsafe_test_suite!(suite_name, KUNIT_TEST_CASES);
+/// ```
+#[macro_export]
+macro_rules! kunit_unsafe_test_suite {
+ ($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;
+ }
+
+ ret
+ };
+
+ // SAFETY: `test_cases` is valid as it should be static.
+ static mut KUNIT_TEST_SUITE: core::cell::UnsafeCell<$crate::bindings::kunit_suite> =
+ core::cell::UnsafeCell::new($crate::bindings::kunit_suite {
+ name: KUNIT_TEST_SUITE_NAME,
+ test_cases: unsafe { $test_cases.as_mut_ptr() },
+ suite_init: None,
+ suite_exit: None,
+ init: None,
+ exit: None,
+ status_comment: [0; 256usize],
+ debugfs: core::ptr::null_mut(),
+ log: core::ptr::null_mut(),
+ suite_init_err: 0,
+ });
+
+ // SAFETY: `KUNIT_TEST_SUITE` is static.
+ #[used]
+ #[link_section = ".kunit_test_suites"]
+ static mut KUNIT_TEST_SUITE_ENTRY: *const $crate::bindings::kunit_suite =
+ unsafe { KUNIT_TEST_SUITE.get() };
+ };
+ };
+}
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 3642cadc34b1..ec81fd28d71a 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -18,6 +18,7 @@
#![feature(new_uninit)]
#![feature(receiver_trait)]
#![feature(unsize)]
+#![feature(const_mut_refs)]

// Ensure conditional compilation based on the kernel configuration works;
// otherwise we may silently break things like initcall handling.

--
2.41.0.255.g8b1d071c50-goog