Improve test coverage

crates/polars-parquet/src/parquet/encoding/byte_stream_split/mod.rs

@@ -41,7 +41,7 @@ mod tests {
     }
 
     #[test]
-    fn fails_for_bad_size() -> Result<(), ParquetError> {
+    fn fails_for_invalid_values_size() -> Result<(), ParquetError> {
         let buffer = vec![0; 12];
 
         let result = Decoder::try_new(&buffer, 8);
@@ -50,6 +50,16 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn fails_for_invalid_element_size() -> Result<(), ParquetError> {
+        let buffer = vec![0; 16];
+
+        let result = Decoder::try_new(&buffer, 16);
+        assert!(result.is_err());
+
+        Ok(())
+    }
+
     fn encode<T: NativeType>(data: &[T], buffer: &mut Vec<u8>) {
         let element_size = std::mem::size_of::<T>();
         let num_elements = data.len();