added productive Code for louder if volume is max

src/main/java/device/radioPlayer/RadioPlayer.java

@@ -29,7 +29,9 @@ public class RadioPlayer implements Device {
 
     @Override
     public void louder() {
-        Lautstaerke+=1;
+        if(Lautstaerke < 100){
+        Lautstaerke+=1;}
+        else Lautstaerke = 100;
     }
 
     @Override

src/test/java/device/radioPlayer/RadioPlayerTest.java

@@ -31,8 +31,8 @@ class RadioPlayerTest {
         rp2.setLautstaerke(100);
         rp2.louder();
         return Stream.of(
-                Arguments.of("Test for one louder", rp1, 1),
-                Arguments.of("Test for one louder", rp2, 100)
+                Arguments.of("Test for one step louder", rp1, 1),
+                Arguments.of("Test for max louder", rp2, 100)
         );
     }