[PATCH v2 18/28] rust: str: add `CStr` unit tests

ojeda
2022-12-02T16:16:20Z

From: Milan Landaverde <milan@mdaverde.com>

Add unit tests for `CStr::from_bytes_with_nul()` and
`CStr::from_bytes_with_nul_unchecked()`.

These serve as an example of the first unit tests for Rust code
(i.e. different from documentation tests).

Signed-off-by: Milan Landaverde <milan@mdaverde.com>
[Reworded, adapted for upstream and applied latest changes]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
rust/kernel/str.rs | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)

diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs
index 11d297c1a61c..3ed685cb5a3c 100644
--- a/rust/kernel/str.rs
+++ b/rust/kernel/str.rs
@@ -321,6 +321,35 @@ where
}
}

+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ #[test]
+ fn test_cstr_to_str() {
+ let good_bytes = b"\xf0\x9f\xa6\x80\0";
+ let checked_cstr = CStr::from_bytes_with_nul(good_bytes).unwrap();
+ let checked_str = checked_cstr.to_str().unwrap();
+ assert_eq!(checked_str, "🦀");
+ }
+
+ #[test]
+ #[should_panic]
+ fn test_cstr_to_str_panic() {
+ let bad_bytes = b"\xc3\x28\0";
+ let checked_cstr = CStr::from_bytes_with_nul(bad_bytes).unwrap();
+ checked_cstr.to_str().unwrap();
+ }
+
+ #[test]
+ fn test_cstr_as_str_unchecked() {
+ let good_bytes = b"\xf0\x9f\x90\xA7\0";
+ let checked_cstr = CStr::from_bytes_with_nul(good_bytes).unwrap();
+ let unchecked_str = unsafe { checked_cstr.as_str_unchecked() };
+ assert_eq!(unchecked_str, "🐧");
+ }
+}
+
/// Allows formatting of [`fmt::Arguments`] into a raw buffer.
///
/// It does not fail if callers write past the end of the buffer so that they can calculate the
--
2.38.1