Method changePlaySource of CDPlayer tested on activeSource=CDWechseler -> shouldReturnCDDrive.

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

@@ -133,7 +133,10 @@ public class CDPlayer implements Device {
         return null;
     }
     public String changePlaySource(){
-        this.activeSource="CDWechseler";
+        if(activeSource.equals("CDDrive")) {
+            this.activeSource = "CDWechseler";
+        }else this.activeSource="CDDrive";
+
         return activeSource;
     }
 

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

@@ -367,14 +367,25 @@ class CDPlayerTest {
     @ParameterizedTest
     @MethodSource("changePlaySourceData")
     void changePlaySourceTest(String testName,String cases, CDPlayer _cdPlayer) {
-        String returnVal=_cdPlayer.changePlaySource();
+
+        if(cases.equals("Case1")) {
+            String returnVal = _cdPlayer.changePlaySource();
             assertThat(returnVal).describedAs(testName).isEqualTo("CDWechseler");
         }
+        if(cases.equals("Case2")) {
+            String returnVal = _cdPlayer.changePlaySource();
+            assertThat(returnVal).describedAs(testName).isEqualTo("CDDrive");
+        }
+    }
     static Stream<Arguments> changePlaySourceData () {
         CDPlayer cdPlayer1 = new CDPlayer();
 
+        CDPlayer cdPlayer2 = new CDPlayer();
+        cdPlayer2.changePlaySource();
+
         return Stream.of(
-                Arguments.of("[changePlaySource() by activeSource=CDDrive ] => shouldReturnCDWechseler","Case1", cdPlayer1)
+                Arguments.of("[changePlaySource() by activeSource=CDDrive ] => shouldReturnCDWechseler","Case1", cdPlayer1),
+                Arguments.of("[changePlaySource() by activeSource=CDWechseler ] => shouldReturnCDDrive","Case2", cdPlayer2)
         );
     }