Update crates/fluss/src/row/encode/iceberg_key_encoder.rs

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: zuston

crates/fluss/src/row/encode/iceberg_key_encoder.rs

@@ -309,6 +309,25 @@ mod tests {
         assert_eq!(encoded.as_ref(), bytes);
     }
 
+    #[test]
+    fn test_char_encoding() {
+        let row_type = RowType::with_data_types_and_field_names(
+            vec![DataTypes::char_type(5)],
+            vec!["char_field"],
+        );
+
+        let value = "hello";
+        let row = GenericRow::from_data(vec![Datum::from(value)]);
+        let mut encoder = IcebergKeyEncoder::create_key_encoder(
+            &row_type,
+            &["char_field".to_string()],
+        )
+        .unwrap();
+
+        let encoded = encoder.encode_key(&row).unwrap();
+        assert_eq!(encoded.as_ref(), value.as_bytes());
+    }
+
     #[test]
     fn test_float_encoding() {
         let row_type =