@@ -272,11 +272,83 @@ macro_rules! kunit_unsafe_test_suite {
};
}
+/// In some cases, you need to call test-only code from outside the test case, for example, to
+/// create a function mock. This function can be invoked to know whether we are currently running a
+/// KUnit test or not.
+///
+/// # Examples
+///
+/// This example shows how a function can be mocked to return a well-known value while testing:
+///
+/// ```
+/// # use kernel::kunit::in_kunit_test;
+/// #
+/// fn fn_mock_example(n: i32) -> i32 {
+/// if in_kunit_test() {
+/// 100
+/// } else {
+/// n + 1
+/// }
+/// }
+///
+/// let mock_res = fn_mock_example(5);
+/// assert_eq!(mock_res, 100);
+/// ```
+///
+/// Sometimes, you don't control the code that needs to be mocked. This example shows how the
+/// `bindings` module can be mocked:
+///
+/// ```
+/// // 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_ {
+/// if in_kunit_test() {
+/// 1234
+/// } else {
+/// unsafe { kernel::bindings::ktime_get_boot_fast_ns() }
+/// }
+/// }
+/// }
+///
+/// // 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() }
+/// }
+///
+/// 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_kunit_tests() {
let running = true;
assert_eq!(running, true);
}
+
+ #[test]
+ fn rust_test_kunit_in_kunit_test() {
+ let in_kunit = in_kunit_test();
+ assert_eq!(in_kunit, true);
+ }
}