Next Production Code in USB Class implemented

src/main/java/device/usbPlayer/UsbPlayer.java

@@ -111,7 +111,9 @@ public class UsbPlayer implements Device {
 
     @Override
     public void next() {
-
+        int currentIdex = Playlist.indexOf(playTrack);
+        int nextIndex = (currentIdex + 1) % Playlist.size();
+        playTrack = Playlist.get(nextIndex);
     }
 
     @Override

src/test/java/device/usbPlayer/UsbPlayerTest.java

@@ -98,18 +98,18 @@ void louderTest(String testName, UsbPlayer inputPlay, int expectedResult) {
         UsbPlayer up1 = new UsbPlayer();
         up1.next();
         UsbPlayer up2 = new UsbPlayer();
-        for (int i = 0; i < up2.getPlaylist().size(); i++) {
+        for (int i = 1; i < up2.getPlaylist().size(); i++) {
             up2.next();
         }
         UsbPlayer up3 = new UsbPlayer();
-        for (int i = 0; i < up3.getPlaylist().size(); i++) {
+        for (int i = 1; i < up3.getPlaylist().size(); i++) {
             up3.next();
         }
         up3.next();
         return Stream.of(
                 Arguments.of("Second-Song : Musik 02.mp3 ", up1, "Musik 02.mp3"),
                 Arguments.of("Last-Song : Musik 03.mp3  ", up2, "Musik 03.mp3"),
-                Arguments.of("From last to first Song : Musik 01.mp3  ", up2, "Musik 01.mp3")
+                Arguments.of("From last to first Song : Musik 01.mp3  ", up3, "Musik 01.mp3")
 
         );
     }