Simplified some code

src/lib.rs

@@ -4,7 +4,6 @@ pub mod types;
 
 pub mod test_util {
     pub mod util {
-
         use std::io::{self, Write};
 
         // Function to save a Vec<u8> to a file
@@ -55,16 +54,14 @@ pub mod test_util {
         pub const TESTFILEDIRECTORY: &str = "tests/sample_tracks3";
 
         pub fn get_filename(track: i32) -> String {
-            let mut filename = String::from("track");
+            const FLAC_EXTENSION: &str = ".flac";
 
-            if track < 10 {
+            let filename = if track < 10 { 
-                filename += "0";
+                format!("track0{}{}", track, FLAC_EXTENSION)
-                filename += &track.to_string();
             } else {
-                filename += &track.to_string();
+                format!("track{}{}", track, FLAC_EXTENSION)
-            }
+            };
 
-            filename += ".flac";
 
             filename
         }