// SPDX-License-Identifier: GPL-2.0
//! KUnit-based macros for Rust unit tests.
//!
//! C header: [`include/kunit/test.h`](srctree/include/kunit/test.h)
//!
//! Reference: <https://docs.kernel.org/dev-tools/kunit/index.html>
use core::{ffi::c_void, fmt};
/// Prints a KUnit error-level message.
///
/// Public but hidden since it should only be used from KUnit generated code.
#[doc(hidden)]
pub fn err(args: fmt::Arguments<'_>) {
// SAFETY: The format string is null-terminated and the `%pA` specifier matches the argument we
// are passing.
#[cfg(CONFIG_PRINTK)]
unsafe {
bindings::_printk(
b"\x013%pA\0".as_ptr() as _,
&args as *const _ as *const c_void,
);
}
}
/// Prints a KUnit info-level message.
///
/// Public but hidden since it should only be used from KUnit generated code.
#[doc(hidden)]
pub fn info(args: fmt::Arguments<'_>) {
// SAFETY: The format string is null-terminated and the `%pA` specifier matches the argument we
// are passing.
#[cfg(CONFIG_PRINTK)]
unsafe {
bindings::_printk(
b"\x016%pA\0".as_ptr() as _,
&args as *const _ as *const c_void,
);
}
}
/// Asserts that a boolean expression is `true` at runtime.
///
/// Public but hidden since it should only be used from generated tests.
///
/// Unlike the one in `core`, this one does not panic; instead, it is mapped to the KUnit
/// facilities. See [`assert!`] for more details.
#[doc(hidden)]
#[macro_export]
macro_rules! kunit_assert {
($name:literal, $file:literal, $diff:expr, $condition:expr $(,)?) => {
'out: {
// Do nothing if the condition is `true`.
if $condition {
break 'out;
}
static FILE: &'static $crate::str::CStr = $crate::c_str!($file);
static LINE: i32 = core::line!() as i32 - $diff;
static CONDITION: &'static $crate::str::CStr = $crate::c_str!(stringify!($condition));
// SAFETY: FFI call without safety requirements.
let kunit_test = unsafe { $crate::bindings::kunit_get_current_test() };
if kunit_test.is_null() {
// The assertion failed but this task is not running a KUnit test, so we cannot call
// KUnit, but at least print an error to the kernel log. This may happen if this
// macro is called from an spawned thread in a test (see
// `scripts/rustdoc_test_gen.rs`) or if some non-test code calls this macro by
// mistake (it is hidden to prevent that).
//
// This mimics KUnit's failed assertion format.
$crate::kunit::err(format_args!(
" # {}: ASSERTION FAILED at {FILE}:{LINE}\n",
$name
));
$crate::kunit::err(format_args!(
" Expected {CONDITION} to be true, but is false\n"
));
$crate::kunit::err(format_args!(
" Failure not reported to KUnit since this is a non-KUnit task\n"
));
break 'out;
}
#[repr(transparent)]
struct Location($crate::bindings::kunit_loc);
#[repr(transparent)]
struct UnaryAssert($crate::bindings::kunit_unary_assert);
// SAFETY: There is only a static instance and in that one the pointer field points to
// an immutable C string.
unsafe impl Sync for Location {}
// SAFETY: There is only a static instance and in that one the pointer field points to
// an immutable C string.
unsafe impl Sync for UnaryAssert {}
static LOCATION: Location = Location($crate::bindings::kunit_loc {
file: FILE.as_char_ptr(),
line: LINE,
});
static ASSERTION: UnaryAssert = UnaryAssert($crate::bindings::kunit_unary_assert {
assert: $crate::bindings::kunit_assert {},
condition: CONDITION.as_char_ptr(),
expected_true: true,
});
// SAFETY:
// - FFI call.
// - The `kunit_test` pointer is valid because we got it from
// `kunit_get_current_test()` and it was not null. This means we are in a KUnit
// test, and that the pointer can be passed to KUnit functions and assertions.
// - The string pointers (`file` and `condition` above) point to null-terminated
// strings since they are `CStr`s.
// - The function pointer (`format`) points to the proper function.
// - The pointers passed will remain valid since they point to `static`s.
// - The format string is allowed to be null.
// - There are, however, problems with this: first of all, this will end up stopping
// the thread, without running destructors. While that is problematic in itself,
// it is considered UB to have what is effectively a forced foreign unwind
// with `extern "C"` ABI. One could observe the stack that is now gone from
// another thread. We should avoid pinning stack variables to prevent library UB,
// too. For the moment, given that test failures are reported immediately before the
// next test runs, that test failures should be fixed and that KUnit is explicitly
// documented as not suitable for production environments, we feel it is reasonable.
unsafe {
$crate::bindings::__kunit_do_failed_assertion(
kunit_test,
core::ptr::addr_of!(LOCATION.0),
$crate::bindings::kunit_assert_type_KUNIT_ASSERTION,
core::ptr::addr_of!(ASSERTION.0.assert),
Some($crate::bindings::kunit_unary_assert_format),
core::ptr::null(),
);
}
// SAFETY: FFI call; the `test` pointer is valid because this hidden macro should only
// be called by the generated documentation tests which forward the test pointer given
// by KUnit.
unsafe {
$crate::bindings::__kunit_abort(kunit_test);
}
}
};
}
/// Asserts that two expressions are equal to each other (using [`PartialEq`]).
///
/// Public but hidden since it should only be used from generated tests.
///
/// Unlike the one in `core`, this one does not panic; instead, it is mapped to the KUnit
/// facilities. See [`assert!`] for more details.
#[doc(hidden)]
#[macro_export]
macro_rules! kunit_assert_eq {
($name:literal, $file:literal, $diff:expr, $left:expr, $right:expr $(,)?) => {{
// For the moment, we just forward to the expression assert because, for binary asserts,
// KUnit supports only a few types (e.g. integers).
$crate::kunit_assert!($name, $file, $diff, $left == $right);
}};
}
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