test(ffi): add mutable buffer tests (#12701)

1 files changed, 9 insertions, 0 deletions

diff --git a/test_ffi/src/lib.rs b/test_ffi/src/lib.rs
index d7fd5182d..38275e547 100644
--- a/test_ffi/src/lib.rs
+++ b/test_ffi/src/lib.rs
@@ -76,6 +76,15 @@ pub extern "C" fn sleep_blocking(ms: u64) {
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+pub extern "C" fn fill_buffer(value: u8, buf: *mut u8, len: usize) {
+  let buf = unsafe { std::slice::from_raw_parts_mut(buf, len) };
+  for itm in buf.iter_mut() {
+    *itm = value;
+  }
+}
+
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[no_mangle]
 pub extern "C" fn nonblocking_buffer(ptr: *const u8, len: usize) {
   let buf = unsafe { std::slice::from_raw_parts(ptr, len) };
   assert_eq!(buf, vec![1, 2, 3, 4, 5, 6, 7, 8]);