diff --git a/retrieval/src/test.rs b/retrieval/src/test.rs
index 5063586..5a6473c 100644
--- a/retrieval/src/test.rs
+++ b/retrieval/src/test.rs
@@ -132,8 +132,19 @@ async fn get_cached_0_inner() -> Result<(), Error> {
 
 #[test]
 fn bufs() {
+    use bytes::{Buf, BufMut};
     let mut buf = BytesMut::with_capacity(1024);
     assert!(buf.as_mut().len() == 0);
     buf.put_u32_le(123);
     assert!(buf.as_mut().len() == 4);
+    let mut b2 = buf.split_to(4);
+    assert!(b2.capacity() == 4);
+    b2.advance(2);
+    assert!(b2.capacity() == 2);
+    b2.advance(2);
+    assert!(b2.capacity() == 0);
+    assert!(buf.capacity() == 1020);
+    assert!(buf.remaining() == 0);
+    assert!(buf.remaining_mut() >= 1020);
+    assert!(buf.capacity() == 1020);
 }