Method changePlaySource of CDPlayer tested on activeSource=CDDrive -> shouldReturnCDWechseler.

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

@@ -20,6 +20,9 @@ public class CDPlayer implements Device {
     private String actualPlayTrack="";
     private CD loadedCD=null;
 
+    private CDWechseler cdWechseler;
+    private String activeSource="CDDrive";//or CDWechseler
+
     @Override
     public void louder() {
         if(volume < 100) {
@@ -48,9 +51,7 @@ public class CDPlayer implements Device {
         List<String> playList =  Arrays.asList(loadedCD.getPlayList());
         int indexOfActualPlayTrack=playList.indexOf(actualPlayTrack);
         int indexOfNextPlayTrack=(indexOfActualPlayTrack+1)%loadedCD.getPlayList().length;
-        //System.out.println("actualIndex= "+indexOfActualPlayTrack);
         this.actualPlayTrack=playList.get(indexOfNextPlayTrack );
-        //System.out.println("nextSong= "+actualPlayTrack);
     }
 
     @Override
@@ -131,6 +132,10 @@ public class CDPlayer implements Device {
         }
         return null;
     }
+    public String changePlaySource(){
+        this.activeSource="CDWechseler";
+        return activeSource;
+    }
 
     //Getters, Setters und SupportMethods
     public void setCD(CD _loadedCD) {
@@ -175,8 +180,10 @@ public class CDPlayer implements Device {
         this.infoText=this.getClass().getSimpleName()+": Item->"+actualPlayTrack+" from Album->"+this.loadedCD.getAlbumName()+" running.";
     }
 
-
     public CD getCD() {
         return this.loadedCD;
     }
+
+
+
 }

src/main/java/device/cdPlayer/CDWechseler.java

@@ -0,0 +1,19 @@
+package device.cdPlayer;
+
+import java.util.List;
+
+public class CDWechseler {
+    private List<CD>CDList;
+    private boolean running=false;
+
+
+    public boolean isRunning() {
+        return running;
+    }
+
+    public void activate() {
+        this.running = true;
+    }
+
+
+}

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

@@ -364,4 +364,20 @@ class CDPlayerTest {
         );
     }
 
+    @ParameterizedTest
+    @MethodSource("changePlaySourceData")
+    void changePlaySourceTest(String testName,String cases, CDPlayer _cdPlayer) {
+        String returnVal=_cdPlayer.changePlaySource();
+        assertThat(returnVal).describedAs(testName).isEqualTo("CDWechseler");
+    }
+    static Stream<Arguments> changePlaySourceData () {
+        CDPlayer cdPlayer1 = new CDPlayer();
+
+        return Stream.of(
+                Arguments.of("[changePlaySource() by activeSource=CDDrive ] => shouldReturnCDWechseler","Case1", cdPlayer1)
+        );
+    }
+
+
+
     }