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 v2: https://lore.kernel.org/linux-kselftest/20241029092422.2884505-1-davidgow@go... - 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/... - 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 | 191 +++++++++++++++++++++++++++++++++++++++++++ rust/kernel/lib.rs | 1 + rust/macros/kunit.rs | 153 ++++++++++++++++++++++++++++++++++ rust/macros/lib.rs | 29 +++++++ 5 files changed, 375 insertions(+) create mode 100644 rust/macros/kunit.rs
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 v2: https://lore.kernel.org/linux-kselftest/20241029092422.2884505-2-davidgow@go... - 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 | 108 +++++++++++++++++++++++++++++++++++++++++++ rust/kernel/lib.rs | 1 + 2 files changed, 109 insertions(+)
diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs index 824da0e9738a..27bc4139d352 100644 --- a/rust/kernel/kunit.rs +++ b/rust/kernel/kunit.rs @@ -161,3 +161,111 @@ 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]; + + let mut i = 0; + while i < name_u8.len() && i < 256 { + 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) }; + }; + }; +} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index b62451f64f6e..d662aa37070f 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -18,6 +18,7 @@ #![feature(inline_const)] #![feature(lint_reasons)] #![feature(unsize)] +#![feature(const_mut_refs)]
// Ensure conditional compilation based on the kernel configuration works; // otherwise we may silently break things like initcall handling.
From: José Expósito jose.exposito89@gmail.com
Add a new procedural macro (`#[kunit_tests(kunit_test_suit_name)]`) to run KUnit tests using a user-space like syntax.
The macro, that should be used on modules, transforms every `#[test]` in a `kunit_case!` and adds a `kunit_unsafe_test_suite!` registering all of them.
The only difference with user-space tests is that instead of using `#[cfg(test)]`, `#[kunit_tests(kunit_test_suit_name)]` is used.
Note that `#[cfg(CONFIG_KUNIT)]` is added so the test module is not compiled when `CONFIG_KUNIT` is set to `n`.
Reviewed-by: David Gow davidgow@google.com Signed-off-by: José Expósito jose.exposito89@gmail.com [Updated to use new const fn.] Signed-off-by: David Gow davidgow@google.com ---
Changes since v2: https://lore.kernel.org/linux-kselftest/20241029092422.2884505-3-davidgow@go... - Include missing rust/macros/kunit.rs file from v2. (Thanks Boqun!) - The proc macro now emits an error if the suite name is too long.
Changes since v1: https://lore.kernel.org/lkml/20230720-rustbind-v1-2-c80db349e3b5@google.com/ - Rebased on top of rust-next - Make use of the new const functions, rather than the kunit_case!() macro.
--- MAINTAINERS | 1 + rust/kernel/kunit.rs | 11 ++++ rust/macros/kunit.rs | 153 +++++++++++++++++++++++++++++++++++++++++++ rust/macros/lib.rs | 29 ++++++++ 4 files changed, 194 insertions(+) create mode 100644 rust/macros/kunit.rs
diff --git a/MAINTAINERS b/MAINTAINERS index b77f4495dcf4..b65035ede675 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -12433,6 +12433,7 @@ F: Documentation/dev-tools/kunit/ F: include/kunit/ F: lib/kunit/ F: rust/kernel/kunit.rs +F: rust/macros/kunit.rs F: scripts/rustdoc_test_* F: tools/testing/kunit/
diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs index 27bc4139d352..ac296467a552 100644 --- a/rust/kernel/kunit.rs +++ b/rust/kernel/kunit.rs @@ -40,6 +40,8 @@ pub fn info(args: fmt::Arguments<'_>) { } }
+use macros::kunit_tests; + /// Asserts that a boolean expression is `true` at runtime. /// /// Public but hidden since it should only be used from generated tests. @@ -269,3 +271,12 @@ macro_rules! kunit_unsafe_test_suite { }; }; } + +#[kunit_tests(rust_kernel_kunit)] +mod tests { + #[test] + fn rust_test_kunit_kunit_tests() { + let running = true; + assert_eq!(running, true); + } +} diff --git a/rust/macros/kunit.rs b/rust/macros/kunit.rs new file mode 100644 index 000000000000..850d268cc96a --- /dev/null +++ b/rust/macros/kunit.rs @@ -0,0 +1,153 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Procedural macro to run KUnit tests using a user-space like syntax. +//! +//! Copyright (c) 2023 José Expósito jose.exposito89@gmail.com + +use proc_macro::{Delimiter, Group, TokenStream, TokenTree}; +use std::fmt::Write; + +pub(crate) fn kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream { + if attr.to_string().is_empty() { + panic!("Missing test name in #[kunit_tests(test_name)] macro") + } + + if attr.to_string().as_bytes().len() > 255 { + panic!("The test suite name `{}` exceeds the maximum length of 255 bytes.", attr) + } + + let mut tokens: Vec<_> = ts.into_iter().collect(); + + // Scan for the "mod" keyword. + tokens + .iter() + .find_map(|token| match token { + TokenTree::Ident(ident) => match ident.to_string().as_str() { + "mod" => Some(true), + _ => None, + }, + _ => None, + }) + .expect("#[kunit_tests(test_name)] attribute should only be applied to modules"); + + // Retrieve the main body. The main body should be the last token tree. + let body = match tokens.pop() { + Some(TokenTree::Group(group)) if group.delimiter() == Delimiter::Brace => group, + _ => panic!("cannot locate main body of module"), + }; + + // Get the functions set as tests. Search for `[test]` -> `fn`. + let mut body_it = body.stream().into_iter(); + let mut tests = Vec::new(); + while let Some(token) = body_it.next() { + match token { + TokenTree::Group(ident) if ident.to_string() == "[test]" => match body_it.next() { + Some(TokenTree::Ident(ident)) if ident.to_string() == "fn" => { + let test_name = match body_it.next() { + Some(TokenTree::Ident(ident)) => ident.to_string(), + _ => continue, + }; + tests.push(test_name); + } + _ => continue, + }, + _ => (), + } + } + + // Add `#[cfg(CONFIG_KUNIT)]` before the module declaration. + let config_kunit = "#[cfg(CONFIG_KUNIT)]".to_owned().parse().unwrap(); + tokens.insert( + 0, + TokenTree::Group(Group::new(Delimiter::None, config_kunit)), + ); + + // Generate the test KUnit test suite and a test case for each `#[test]`. + // The code generated for the following test module: + // + // ``` + // #[kunit_tests(kunit_test_suit_name)] + // mod tests { + // #[test] + // fn foo() { + // assert_eq!(1, 1); + // } + // + // #[test] + // fn bar() { + // assert_eq!(2, 2); + // } + // ``` + // + // Looks like: + // + // ``` + // unsafe extern "C" fn kunit_rust_wrapper_foo(_test: *mut kernel::bindings::kunit) { + // foo(); + // } + // static mut KUNIT_CASE_FOO: kernel::bindings::kunit_case = + // kernel::kunit::kunit_case(foo, kunit_rust_wrapper_foo); + // + // unsafe extern "C" fn kunit_rust_wrapper_bar(_test: * mut kernel::bindings::kunit) { + // bar(); + // } + // static mut KUNIT_CASE_BAR: kernel::bindings::kunit_case = + // kernel::kunit::kunit_case(bar, kunit_rust_wrapper_bar); + // + // static mut KUNIT_CASE_NULL: kernel::bindings::kunit_case = kernel::kunit::kunit_case_null(); + // + // static mut TEST_CASES : &mut[kernel::bindings::kunit_case] = unsafe { + // &mut [KUNIT_CASE_FOO, KUNIT_CASE_BAR, KUNIT_CASE_NULL] + // }; + // + // kernel::kunit_unsafe_test_suite!(kunit_test_suit_name, TEST_CASES); + // ``` + let mut kunit_macros = "".to_owned(); + let mut test_cases = "".to_owned(); + for test in tests { + let kunit_wrapper_fn_name = format!("kunit_rust_wrapper_{}", test); + let kunit_case_name = format!("KUNIT_CASE_{}", test.to_uppercase()); + let kunit_wrapper = format!( + "unsafe extern "C" fn {}(_test: *mut kernel::bindings::kunit) {{ {}(); }}", + kunit_wrapper_fn_name, test + ); + let kunit_case = format!( + "static mut {}: kernel::bindings::kunit_case = kernel::kunit::kunit_case(kernel::c_str!("{}"), {});", + kunit_case_name, test, kunit_wrapper_fn_name + ); + writeln!(kunit_macros, "{kunit_wrapper}").unwrap(); + writeln!(kunit_macros, "{kunit_case}").unwrap(); + writeln!(test_cases, "{kunit_case_name},").unwrap(); + } + + writeln!( + kunit_macros, + "static mut KUNIT_CASE_NULL: kernel::bindings::kunit_case = kernel::kunit::kunit_case_null();" + ) + .unwrap(); + + writeln!( + kunit_macros, + "static mut TEST_CASES : &mut[kernel::bindings::kunit_case] = unsafe {{ &mut[{test_cases} KUNIT_CASE_NULL] }};" + ) + .unwrap(); + + writeln!( + kunit_macros, + "kernel::kunit_unsafe_test_suite!({attr}, TEST_CASES);" + ) + .unwrap(); + + let new_body: TokenStream = vec![body.stream(), kunit_macros.parse().unwrap()] + .into_iter() + .collect(); + + // Remove the `#[test]` macros. + let new_body = new_body.to_string().replace("#[test]", ""); + tokens.push(TokenTree::Group(Group::new( + Delimiter::Brace, + new_body.parse().unwrap(), + ))); + + tokens.into_iter().collect() +} diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs index 939ae00b723a..098925b99982 100644 --- a/rust/macros/lib.rs +++ b/rust/macros/lib.rs @@ -10,6 +10,7 @@ mod quote; mod concat_idents; mod helpers; +mod kunit; mod module; mod paste; mod pin_data; @@ -430,3 +431,31 @@ pub fn paste(input: TokenStream) -> TokenStream { pub fn derive_zeroable(input: TokenStream) -> TokenStream { zeroable::derive(input) } + +/// Registers a KUnit test suite and its test cases using a user-space like syntax. +/// +/// This macro should be used on modules. If `CONFIG_KUNIT` (in `.config`) is `n`, the target module +/// is ignored. +/// +/// # Examples +/// +/// ```ignore +/// # use macros::kunit_tests; +/// +/// #[kunit_tests(kunit_test_suit_name)] +/// mod tests { +/// #[test] +/// fn foo() { +/// assert_eq!(1, 1); +/// } +/// +/// #[test] +/// fn bar() { +/// assert_eq!(2, 2); +/// } +/// } +/// ``` +#[proc_macro_attribute] +pub fn kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream { + kunit::kunit_tests(attr, ts) +}
On Wed, Oct 30, 2024 at 12:57:14PM +0800, David Gow wrote:
From: José Expósito jose.exposito89@gmail.com Add a new procedural macro (`#[kunit_tests(kunit_test_suit_name)]`) to run KUnit tests using a user-space like syntax.
The macro, that should be used on modules, transforms every `#[test]` in a `kunit_case!` and adds a `kunit_unsafe_test_suite!` registering all of them.
The only difference with user-space tests is that instead of using `#[cfg(test)]`, `#[kunit_tests(kunit_test_suit_name)]` is used.
Note that `#[cfg(CONFIG_KUNIT)]` is added so the test module is not compiled when `CONFIG_KUNIT` is set to `n`.
Reviewed-by: David Gow davidgow@google.com Signed-off-by: José Expósito jose.exposito89@gmail.com [Updated to use new const fn.] Signed-off-by: David Gow davidgow@google.com
Changes since v2: https://lore.kernel.org/linux-kselftest/20241029092422.2884505-3-davidgow@go...
- Include missing rust/macros/kunit.rs file from v2. (Thanks Boqun!)
- The proc macro now emits an error if the suite name is too long.
Changes since v1: https://lore.kernel.org/lkml/20230720-rustbind-v1-2-c80db349e3b5@google.com/
- Rebased on top of rust-next
- Make use of the new const functions, rather than the kunit_case!() macro.
MAINTAINERS | 1 + rust/kernel/kunit.rs | 11 ++++ rust/macros/kunit.rs | 153 +++++++++++++++++++++++++++++++++++++++++++ rust/macros/lib.rs | 29 ++++++++ 4 files changed, 194 insertions(+) create mode 100644 rust/macros/kunit.rs
diff --git a/MAINTAINERS b/MAINTAINERS index b77f4495dcf4..b65035ede675 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -12433,6 +12433,7 @@ F: Documentation/dev-tools/kunit/ F: include/kunit/ F: lib/kunit/ F: rust/kernel/kunit.rs +F: rust/macros/kunit.rs F: scripts/rustdoc_test_* F: tools/testing/kunit/ diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs index 27bc4139d352..ac296467a552 100644 --- a/rust/kernel/kunit.rs +++ b/rust/kernel/kunit.rs @@ -40,6 +40,8 @@ pub fn info(args: fmt::Arguments<'_>) { } } +use macros::kunit_tests;
/// Asserts that a boolean expression is `true` at runtime. /// /// Public but hidden since it should only be used from generated tests. @@ -269,3 +271,12 @@ macro_rules! kunit_unsafe_test_suite { }; }; }
+#[kunit_tests(rust_kernel_kunit)] +mod tests {
- #[test]
- fn rust_test_kunit_kunit_tests() {
let running = true;
assert_eq!(running, true);
- }
+} diff --git a/rust/macros/kunit.rs b/rust/macros/kunit.rs new file mode 100644 index 000000000000..850d268cc96a --- /dev/null +++ b/rust/macros/kunit.rs @@ -0,0 +1,153 @@ +// SPDX-License-Identifier: GPL-2.0
+//! Procedural macro to run KUnit tests using a user-space like syntax. +//! +//! Copyright (c) 2023 José Expósito jose.exposito89@gmail.com
+use proc_macro::{Delimiter, Group, TokenStream, TokenTree}; +use std::fmt::Write;
+pub(crate) fn kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream {
- if attr.to_string().is_empty() {
panic!("Missing test name in #[kunit_tests(test_name)] macro")
- }
- if attr.to_string().as_bytes().len() > 255 {
panic!("The test suite name `{}` exceeds the maximum length of 255 bytes.", attr)
- }
- let mut tokens: Vec<_> = ts.into_iter().collect();
- // Scan for the "mod" keyword.
- tokens
.iter()
.find_map(|token| match token {
TokenTree::Ident(ident) => match ident.to_string().as_str() {
"mod" => Some(true),
_ => None,
},
_ => None,
})
.expect("#[kunit_tests(test_name)] attribute should only be applied to modules");
- // Retrieve the main body. The main body should be the last token tree.
- let body = match tokens.pop() {
Some(TokenTree::Group(group)) if group.delimiter() == Delimiter::Brace => group,
_ => panic!("cannot locate main body of module"),
- };
- // Get the functions set as tests. Search for `[test]` -> `fn`.
- let mut body_it = body.stream().into_iter();
- let mut tests = Vec::new();
- while let Some(token) = body_it.next() {
match token {
TokenTree::Group(ident) if ident.to_string() == "[test]" => match body_it.next() {
Some(TokenTree::Ident(ident)) if ident.to_string() == "fn" => {
let test_name = match body_it.next() {
Some(TokenTree::Ident(ident)) => ident.to_string(),
_ => continue,
};
tests.push(test_name);
}
_ => continue,
},
_ => (),
}
- }
- // Add `#[cfg(CONFIG_KUNIT)]` before the module declaration.
- let config_kunit = "#[cfg(CONFIG_KUNIT)]".to_owned().parse().unwrap();
- tokens.insert(
0,
TokenTree::Group(Group::new(Delimiter::None, config_kunit)),
- );
- // Generate the test KUnit test suite and a test case for each `#[test]`.
- // The code generated for the following test module:
- //
- // ```
- // #[kunit_tests(kunit_test_suit_name)]
- // mod tests {
- // #[test]
- // fn foo() {
- // assert_eq!(1, 1);
- // }
- //
- // #[test]
- // fn bar() {
- // assert_eq!(2, 2);
- // }
- // ```
- //
- // Looks like:
- //
- // ```
- // unsafe extern "C" fn kunit_rust_wrapper_foo(_test: *mut kernel::bindings::kunit) {
- // foo();
- // }
- // static mut KUNIT_CASE_FOO: kernel::bindings::kunit_case =
- // kernel::kunit::kunit_case(foo, kunit_rust_wrapper_foo);
- //
- // unsafe extern "C" fn kunit_rust_wrapper_bar(_test: * mut kernel::bindings::kunit) {
- // bar();
- // }
- // static mut KUNIT_CASE_BAR: kernel::bindings::kunit_case =
- // kernel::kunit::kunit_case(bar, kunit_rust_wrapper_bar);
- //
- // static mut KUNIT_CASE_NULL: kernel::bindings::kunit_case = kernel::kunit::kunit_case_null();
- //
- // static mut TEST_CASES : &mut[kernel::bindings::kunit_case] = unsafe {
- // &mut [KUNIT_CASE_FOO, KUNIT_CASE_BAR, KUNIT_CASE_NULL]
- // };
- //
- // kernel::kunit_unsafe_test_suite!(kunit_test_suit_name, TEST_CASES);
- // ```
- let mut kunit_macros = "".to_owned();
- let mut test_cases = "".to_owned();
- for test in tests {
let kunit_wrapper_fn_name = format!("kunit_rust_wrapper_{}", test);
let kunit_case_name = format!("KUNIT_CASE_{}", test.to_uppercase());
let kunit_wrapper = format!(
"unsafe extern \"C\" fn {}(_test: *mut kernel::bindings::kunit) {{ {}(); }}",
kunit_wrapper_fn_name, test
);
let kunit_case = format!(
"static mut {}: kernel::bindings::kunit_case = kernel::kunit::kunit_case(kernel::c_str!(\"{}\"), {});",
kunit_case_name, test, kunit_wrapper_fn_name
);
writeln!(kunit_macros, "{kunit_wrapper}").unwrap();
writeln!(kunit_macros, "{kunit_case}").unwrap();
writeln!(test_cases, "{kunit_case_name},").unwrap();
- }
- writeln!(
kunit_macros,
"static mut KUNIT_CASE_NULL: kernel::bindings::kunit_case = kernel::kunit::kunit_case_null();"
- )
- .unwrap();
- writeln!(
kunit_macros,
"static mut TEST_CASES : &mut[kernel::bindings::kunit_case] = unsafe {{ &mut[{test_cases} KUNIT_CASE_NULL] }};"
- )
- .unwrap();
- writeln!(
kunit_macros,
"kernel::kunit_unsafe_test_suite!({attr}, TEST_CASES);"
- )
- .unwrap();
- let new_body: TokenStream = vec![body.stream(), kunit_macros.parse().unwrap()]
.into_iter()
.collect();
- // Remove the `#[test]` macros.
- let new_body = new_body.to_string().replace("#[test]", "");
Yeah, I want to see how you do it this time ;-) So if you do a `.to_string()` on a `TokenStream`, you lose all the span [1] information ("span information" is a term invited by me, hope I get it right ;-)) e.g. if there is a compile error in the test code, the compiler cannot report the exact line of the error, it can only report there is an error.
Last time I find how to preserve the Span:
https://lore.kernel.org/rust-for-linux/ZMba0_XXZuTgWyWY@boqun-archlinux/
Hope it helps!
[1]: https://doc.rust-lang.org/proc_macro/struct.Span.html
Regards, Boqun
- tokens.push(TokenTree::Group(Group::new(
Delimiter::Brace,
new_body.parse().unwrap(),
- )));
- tokens.into_iter().collect()
+} diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs index 939ae00b723a..098925b99982 100644 --- a/rust/macros/lib.rs +++ b/rust/macros/lib.rs @@ -10,6 +10,7 @@ mod quote; mod concat_idents; mod helpers; +mod kunit; mod module; mod paste; mod pin_data; @@ -430,3 +431,31 @@ pub fn paste(input: TokenStream) -> TokenStream { pub fn derive_zeroable(input: TokenStream) -> TokenStream { zeroable::derive(input) }
+/// Registers a KUnit test suite and its test cases using a user-space like syntax. +/// +/// This macro should be used on modules. If `CONFIG_KUNIT` (in `.config`) is `n`, the target module +/// is ignored. +/// +/// # Examples +/// +/// ```ignore +/// # use macros::kunit_tests; +/// +/// #[kunit_tests(kunit_test_suit_name)] +/// mod tests { +/// #[test] +/// fn foo() { +/// assert_eq!(1, 1); +/// } +/// +/// #[test] +/// fn bar() { +/// assert_eq!(2, 2); +/// } +/// } +/// ``` +#[proc_macro_attribute] +pub fn kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream {
- kunit::kunit_tests(attr, ts)
+}
2.47.0.163.g1226f6d8fa-goog
On Tue, Oct 29, 2024 at 10:11:38PM -0700, Boqun Feng wrote: [...]
- let new_body: TokenStream = vec![body.stream(), kunit_macros.parse().unwrap()]
.into_iter()
.collect();
- // Remove the `#[test]` macros.
- let new_body = new_body.to_string().replace("#[test]", "");
Yeah, I want to see how you do it this time ;-) So if you do a `.to_string()` on a `TokenStream`, you lose all the span [1] information ("span information" is a term invited by me, hope I get it right ;-))
Not important: I meant I am not a procdure macro expert, hope "span information" is what is used when discussing span preservation ;-)
Regards, Boqun
e.g. if there is a compile error in the test code, the compiler cannot report the exact line of the error, it can only report there is an error.
[...]
On Wed, 30 Oct 2024 at 13:11, Boqun Feng boqun.feng@gmail.com wrote:
On Wed, Oct 30, 2024 at 12:57:14PM +0800, David Gow wrote:
From: José Expósito jose.exposito89@gmail.com Add a new procedural macro (`#[kunit_tests(kunit_test_suit_name)]`) to run KUnit tests using a user-space like syntax.
The macro, that should be used on modules, transforms every `#[test]` in a `kunit_case!` and adds a `kunit_unsafe_test_suite!` registering all of them.
The only difference with user-space tests is that instead of using `#[cfg(test)]`, `#[kunit_tests(kunit_test_suit_name)]` is used.
Note that `#[cfg(CONFIG_KUNIT)]` is added so the test module is not compiled when `CONFIG_KUNIT` is set to `n`.
Reviewed-by: David Gow davidgow@google.com Signed-off-by: José Expósito jose.exposito89@gmail.com [Updated to use new const fn.] Signed-off-by: David Gow davidgow@google.com
Changes since v2: https://lore.kernel.org/linux-kselftest/20241029092422.2884505-3-davidgow@go...
- Include missing rust/macros/kunit.rs file from v2. (Thanks Boqun!)
- The proc macro now emits an error if the suite name is too long.
Changes since v1: https://lore.kernel.org/lkml/20230720-rustbind-v1-2-c80db349e3b5@google.com/
- Rebased on top of rust-next
- Make use of the new const functions, rather than the kunit_case!() macro.
MAINTAINERS | 1 + rust/kernel/kunit.rs | 11 ++++ rust/macros/kunit.rs | 153 +++++++++++++++++++++++++++++++++++++++++++ rust/macros/lib.rs | 29 ++++++++ 4 files changed, 194 insertions(+) create mode 100644 rust/macros/kunit.rs
(...snip...)
- let new_body: TokenStream = vec![body.stream(), kunit_macros.parse().unwrap()]
.into_iter()
.collect();
- // Remove the `#[test]` macros.
- let new_body = new_body.to_string().replace("#[test]", "");
Yeah, I want to see how you do it this time ;-) So if you do a `.to_string()` on a `TokenStream`, you lose all the span [1] information ("span information" is a term invited by me, hope I get it right ;-)) e.g. if there is a compile error in the test code, the compiler cannot report the exact line of the error, it can only report there is an error.
Last time I find how to preserve the Span:
https://lore.kernel.org/rust-for-linux/ZMba0_XXZuTgWyWY@boqun-archlinux/
Hope it helps!
Regards, Boqun
Thanks. I managed to get this working, but just ended up with an uglier version of your change, so I've copied it in and added you as a co-developer for this patch in v4.
It made clippy catch a couple of warnings in the example tests, too, so it's clearly working well.
Cheers, -- David
From: José Expósito jose.exposito89@gmail.com
In some cases, we need to call test-only code from outside the test case, for example, to mock a function or a module.
In order to check whether we are in a test or not, we need to test if `CONFIG_KUNIT` is set. Unfortunately, we cannot rely only on this condition because: - a test could be running in another thread, - some distros compile KUnit in production kernels, so checking at runtime that `current->kunit_test != NULL` is required.
Forturately, KUnit provides an optimised check in `kunit_get_current_test()`, which checks CONFIG_KUNIT, a global static key, and then the current thread's running KUnit test.
Add a safe wrapper function around this to know whether or not we are in a KUnit test and examples showing how to mock a function and a module.
Signed-off-by: José Expósito jose.exposito89@gmail.com Co-developed-by: David Gow davidgow@google.com Signed-off-by: David Gow davidgow@google.com ---
No changes since v2: https://lore.kernel.org/linux-kselftest/20241029092422.2884505-4-davidgow@go...
Changes since v1: https://lore.kernel.org/lkml/20230720-rustbind-v1-3-c80db349e3b5@google.com/ - Rebased on top of rust-next. - Use the `kunit_get_current_test()` C function, which wasn't previously available, instead of rolling our own. - (Thanks also to Boqun for suggesting a nicer way of implementing this, which I tried, but the `kunit_get_current_test()` version obsoleted.)
--- rust/kernel/kunit.rs | 72 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 72 insertions(+)
diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs index ac296467a552..d5926f7ef405 100644 --- a/rust/kernel/kunit.rs +++ b/rust/kernel/kunit.rs @@ -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); + } }
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