UsbPlayerTest.louderTest third Case

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

@@ -116,12 +116,14 @@ public class UsbPlayer implements Device {
 
     @Override
     public void louder() {
+        if(this.soundWas == -1) {
             if (Lautstaerke < 100) {
                 Lautstaerke += 1;
             } else {
                 Lautstaerke = 100;
             }
         }
+    }
 
     public void Louder_10() {
         Lautstaerke += 10;

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

@@ -59,14 +59,25 @@ class UsbPlayerTest {
 
     static Stream<Arguments> louderOptions() {
         USB_Stick USBDrive = new USB_Stick();
+        //first case
         UsbPlayer up11 = new UsbPlayer(USBDrive);
         up11.louder();
+        //second case
         UsbPlayer up22 = new UsbPlayer(USBDrive);
         up22.setLautstaerke(100);
         up22.louder();
+        //third case
+        UsbPlayer up3 = new UsbPlayer(USBDrive);
+        up3.setLautstaerke(100);
+        up3.mute();
+        up3.louder();
+
+
+
         return Stream.of(
                 Arguments.of("Volume is : 1 ", up11, 1),
-                Arguments.of("Volume is : 100 ", up22, 100)
+                Arguments.of("Volume is : 100 ", up22, 100),
+                Arguments.of("Volume is muted,no change can be made ", up3, 0)
         );
     }