fixup! Refactor attributes API

src/tests.rs

@@ -443,6 +443,21 @@ fn attributes() {
         assert_eq!(data, attribute.data());
         assert_eq!(data.len(), attribute.total_size());
 
+        // if the buffer is smaller than the attribute, it is truncated and the
+        // full size is returned
+        let mut small_buffer = [0; 5];
+        let attribute = fs.attribute(filename, 37, &mut small_buffer)?.unwrap();
+        assert_eq!(&data[..5], attribute.data());
+        assert_eq!(data.len(), attribute.total_size());
+
+        // if the input data is too long, an error is returned
+        let long_data = &[0xff; 1024];
+        assert!(long_data.len() > Attribute::MAX_SIZE as _);
+        assert_eq!(
+            Err(Error::NO_SPACE),
+            fs.set_attribute(filename, 37, long_data)
+        );
+
         // // not sure if we should have this method (may be quite expensive)
         // let attributes = unsafe { fs.attributes("some.file", &mut storage).unwrap() };
         // assert!(attributes[37]);