The `kunit_test` proc macro only checks for the `test` attribute immediately preceding a `fn`. If the function is disabled via a `cfg`, the generated code would result in a compile error referencing a non-existent function [1].
This collects attributes and specifically cherry-picks `cfg` attributes to be duplicated inside KUnit wrapper functions such that a test function disabled via `cfg` compiles and is marked as skipped in KUnit correctly. Link: https://lore.kernel.org/rust-for-linux/CANiq72==48=69hYiDo1321pCzgn_n1_jg=ez5uyxx91c+g5...@mail.gmail.com/ [1] Closes: https://github.com/Rust-for-Linux/linux/issues/1185 Suggested-by: Miguel Ojeda <[email protected]> Suggested-by: David Gow <[email protected]> Signed-off-by: Kaibo Ma <[email protected]> --- v1 -> v2: applied suggestion such that cfg'd out tests show as skipped on KUnit rust/kernel/kunit.rs | 7 +++++++ rust/macros/kunit.rs | 48 +++++++++++++++++++++++++++++++++----------- 2 files changed, 43 insertions(+), 12 deletions(-) diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs index 41efd8759..32640dfc9 100644 --- a/rust/kernel/kunit.rs +++ b/rust/kernel/kunit.rs @@ -357,4 +357,11 @@ fn rust_test_kunit_example_test() { fn rust_test_kunit_in_kunit_test() { assert!(in_kunit_test()); } + + #[test] + #[cfg(not(all()))] + fn rust_test_kunit_always_disabled_test() { + // This test should never run because of the `cfg`. + assert!(false); + } } diff --git a/rust/macros/kunit.rs b/rust/macros/kunit.rs index 81d18149a..b395bb053 100644 --- a/rust/macros/kunit.rs +++ b/rust/macros/kunit.rs @@ -5,6 +5,7 @@ //! Copyright (c) 2023 José Expósito <[email protected]> use proc_macro::{Delimiter, Group, TokenStream, TokenTree}; +use std::collections::HashMap; use std::fmt::Write; pub(crate) fn kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream { @@ -41,20 +42,32 @@ pub(crate) fn kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream { // Get the functions set as tests. Search for `[test]` -> `fn`. let mut body_it = body.stream().into_iter(); let mut tests = Vec::new(); + let mut attributes: HashMap<String, TokenStream> = HashMap::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); + TokenTree::Punct(ref p) if p.as_char() == '#' => match body_it.next() { + Some(TokenTree::Group(g)) if g.delimiter() == Delimiter::Bracket => { + if let Some(TokenTree::Ident(name)) = g.stream().into_iter().next() { + // Collect attributes because we need to find which are tests. We also + // need to copy `cfg` attributes so tests can be conditionally enabled. + attributes + .entry(name.to_string()) + .or_default() + .extend([token, TokenTree::Group(g)]); + } + continue; } - _ => continue, + _ => (), }, + TokenTree::Ident(i) if i.to_string() == "fn" && attributes.contains_key("test") => { + if let Some(TokenTree::Ident(test_name)) = body_it.next() { + tests.push((test_name, attributes.remove("cfg").unwrap_or_default())) + } + } + _ => (), } + attributes.clear(); } // Add `#[cfg(CONFIG_KUNIT="y")]` before the module declaration. @@ -100,11 +113,22 @@ pub(crate) fn kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream { let mut test_cases = "".to_owned(); let mut assert_macros = "".to_owned(); let path = crate::helpers::file(); - for test in &tests { + let num_tests = tests.len(); + for (test, cfg_attr) 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. + // Append any `cfg` attributes the user might have written on their tests so we don't + // attempt to call them when they are `cfg`'d out. An extra `use` is used here to reduce + // the length of the assert message. let kunit_wrapper = format!( - "unsafe extern \"C\" fn {kunit_wrapper_fn_name}(_test: *mut ::kernel::bindings::kunit) {{ use ::kernel::kunit::is_test_result_ok; assert!(is_test_result_ok({test}())); }}", + r#"unsafe extern "C" fn {kunit_wrapper_fn_name}(_test: *mut ::kernel::bindings::kunit) + {{ + (*_test).status = ::kernel::bindings::kunit_status_KUNIT_SKIPPED; + {cfg_attr} {{ + (*_test).status = ::kernel::bindings::kunit_status_KUNIT_SUCCESS; + use ::kernel::kunit::is_test_result_ok; + assert!(is_test_result_ok({test}())); + }} + }}"#, ); writeln!(kunit_macros, "{kunit_wrapper}").unwrap(); writeln!( @@ -139,7 +163,7 @@ macro_rules! assert_eq {{ writeln!( kunit_macros, "static mut TEST_CASES: [::kernel::bindings::kunit_case; {}] = [\n{test_cases} ::kernel::kunit::kunit_case_null(),\n];", - tests.len() + 1 + num_tests + 1 ) .unwrap(); -- 2.50.1
