fix: output points to a file

src/pass_second.rs

@@ -32,7 +32,7 @@ mod tests {
     fn simple_encryption() {
         let input_path = Path::new("tests/data/test.nt");
         let config_path = Path::new("tests/data/config.yaml");
-        let output_path = Path::new("tests/data/");
+        let output_path = Path::new("tests/data/output.nt");
         let type_map_path = Path::new("tests/data/type_map.nt");
         let logger = log::create_logger(true);
         encrypt(