Method mute of CDPlayer tested after 2x louder() by checkingTheVolume -> VolumeShouldBeSetTo0.

src/main/java/device/cdPlayer/CDPlayer.java

@@ -112,6 +112,7 @@ public class CDPlayer implements Device {
     @Override
     public String mute() {
         muted=true;
+        volume=0;
         return ("Volume muted.");
     }
 

src/test/java/device/cdPlayer/CDPlayerTest.java

@@ -541,12 +541,19 @@ class CDPlayerTest {
             _cdPlayer.mute();
             assertThat(_cdPlayer.isMuted()).describedAs(testName).isEqualTo(true);
         }
+        if(cases.equals("Case3")) {
+            _cdPlayer.louder();
+            _cdPlayer.louder();
+            _cdPlayer.mute();
+            assertThat(_cdPlayer.getVolume()).describedAs(testName).isEqualTo(0);
+        }
     }
     static Stream<Arguments> muteTestData () {
         CDPlayer cdPlayer1 = new CDPlayer();
         return Stream.of(
                 Arguments.of("[mute() by checkingTheReturnValue ] => ShouldReturnAString", "Case1", cdPlayer1, "Volume muted."),
-                Arguments.of("[mute() by checkingTheEffectAfterRun ] => VariableMutedShouldBeTrue", "Case2", cdPlayer1, "Volume muted.")
+                Arguments.of("[mute() by checkingTheEffectAfterRun ] => VariableMutedShouldBeTrue", "Case2", cdPlayer1, "Volume muted."),
+                Arguments.of("[mute() after 2x louder() by checkingTheVolume] => VolumeShouldBeSetTo0", "Case3", cdPlayer1, "Volume muted.")
         );
     }