Method mute of CDPlayer tested on checkingTheEffectAfterRun -> VariableMutedShouldBeFalse.

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

@@ -120,6 +120,7 @@ public class CDPlayer implements Device {
 
     @Override
     public String unmute() {
+        muted=false;
         return ("Volume unmute.");
     }
 

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

@@ -568,12 +568,20 @@ class CDPlayerTest {
     @ParameterizedTest
     @MethodSource("unmuteTestData")
     void unmuteTest(String testName,String cases, CDPlayer _cdPlayer,String expectedResult) {
-        assertThat(_cdPlayer.unmute()).describedAs(testName).isEqualTo(expectedResult);
+        if(cases.equals("Case1")) {
+            assertThat(_cdPlayer.unmute()).describedAs(testName).isEqualTo(expectedResult);
+        }
+        if(cases.equals("Case2")) {
+            _cdPlayer.unmute();
+            assertThat(_cdPlayer.isMuted()).describedAs(testName).isEqualTo(false);
+        }
     }
     static Stream<Arguments> unmuteTestData () {
         CDPlayer cdPlayer1 = new CDPlayer();
+        cdPlayer1.mute();
         return Stream.of(
-                Arguments.of("[unmute() by checkingTheReturnValue ] => ShouldReturnAString", "Case1", cdPlayer1, "Volume unmute.")
+                Arguments.of("[unmute() by checkingTheReturnValue ] => ShouldReturnAString", "Case1", cdPlayer1, "Volume unmute."),
+                Arguments.of("[unmute() by checkingTheEffectAfterRun ] => VariableMutedShouldBeFalse", "Case2", cdPlayer1, "Volume unmute.")
         );
     }