implemented Test for louder max

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

@@ -25,10 +25,14 @@ class RadioPlayerTest {
 
     static Stream<Arguments> quieterLouderOptions() {
         RadioPlayer rp1 = new RadioPlayer();
+        RadioPlayer rp2 = new RadioPlayer();
         rp1.setLautstaerke(0);
         rp1.louder();
+        rp2.setLautstaerke(100);
+        rp2.louder();
         return Stream.of(
-                Arguments.of("Test for one louder", rp1, 1)
+                Arguments.of("Test for one louder", rp1, 1),
+                Arguments.of("Test for one louder", rp2, 100)
         );
     }