1 files changed, 66 insertions, 0 deletions
diff --git a/library/std/src/sys/common/tests.rs b/library/std/src/sys/common/tests.rs
new file mode 100644
index 000000000..fb6f5d6af
--- /dev/null
+++ b/library/std/src/sys/common/tests.rs
@@ -0,0 +1,66 @@
+use crate::ffi::CString;
+use crate::hint::black_box;
+use crate::path::Path;
+use crate::sys::common::small_c_string::run_path_with_cstr;
+use core::iter::repeat;
+
+#[test]
+fn stack_allocation_works() {
+    let path = Path::new("abc");
+    let result = run_path_with_cstr(path, |p| {
+        assert_eq!(p, &*CString::new(path.as_os_str().bytes()).unwrap());
+        Ok(42)
+    });
+    assert_eq!(result.unwrap(), 42);
+}
+
+#[test]
+fn stack_allocation_fails() {
+    let path = Path::new("ab\0");
+    assert!(run_path_with_cstr::<(), _>(path, |_| unreachable!()).is_err());
+}
+
+#[test]
+fn heap_allocation_works() {
+    let path = repeat("a").take(384).collect::<String>();
+    let path = Path::new(&path);
+    let result = run_path_with_cstr(path, |p| {
+        assert_eq!(p, &*CString::new(path.as_os_str().bytes()).unwrap());
+        Ok(42)
+    });
+    assert_eq!(result.unwrap(), 42);
+}
+
+#[test]
+fn heap_allocation_fails() {
+    let mut path = repeat("a").take(384).collect::<String>();
+    path.push('\0');
+    let path = Path::new(&path);
+    assert!(run_path_with_cstr::<(), _>(path, |_| unreachable!()).is_err());
+}
+
+#[bench]
+fn bench_stack_path_alloc(b: &mut test::Bencher) {
+    let path = repeat("a").take(383).collect::<String>();
+    let p = Path::new(&path);
+    b.iter(|| {
+        run_path_with_cstr(p, |cstr| {
+            black_box(cstr);
+            Ok(())
+        })
+        .unwrap();
+    });
+}
+
+#[bench]
+fn bench_heap_path_alloc(b: &mut test::Bencher) {
+    let path = repeat("a").take(384).collect::<String>();
+    let p = Path::new(&path);
+    b.iter(|| {
+        run_path_with_cstr(p, |cstr| {
+            black_box(cstr);
+            Ok(())
+        })
+        .unwrap();
+    });
+}