Method loadCDWechseler of CDPlayer tested on notRunning=CDWechseler -> shouldThrowAnException.

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

@@ -20,7 +20,7 @@ public class CDPlayer implements Device {
     private String actualPlayTrack="";
     private CD loadedCD=null;
 
-    private CDWechseler cdWechseler;
+    private CDWechseler cdWechseler=null;
     private String activeSource="CDDrive";//or CDWechseler
 
     @Override
@@ -139,6 +139,11 @@ public class CDPlayer implements Device {
 
         return activeSource;
     }
+    public void loadCDWechseler(List<CD>cdList){
+        if(cdWechseler==null||!cdWechseler.isRunning()){
+            throw new CDWechselerNotRunningException();
+        }
+    }
 
     //Getters, Setters und SupportMethods
     public void setCD(CD _loadedCD) {

src/main/java/device/cdPlayer/exceptions/CDWechselerNotRunningException.java

@@ -0,0 +1,8 @@
+package device.cdPlayer.exceptions;
+
+public class CDWechselerNotRunningException extends RuntimeException {
+
+    public CDWechselerNotRunningException() {
+        super("CDWechseler must be active for using.");
+    }
+}

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

@@ -389,6 +389,22 @@ class CDPlayerTest {
         );
     }
 
+    @ParameterizedTest
+    @MethodSource("loadCDWechselerData")
+    void loadCDWechselerTest(String testName,String cases, CDPlayer _cdPlayer,List<CD>cdList,Exception exception) {
+        Exception newException = assertThrows(exception.getClass(), () -> _cdPlayer.loadCDWechseler(cdList));
+        assertEquals(CDWechselerNotRunningException.class, newException.getClass());
+    }
+    static Stream<Arguments> loadCDWechselerData () {
+        CDPlayer cdPlayer1 = new CDPlayer();
+        String[] audioPlayList=new String[]{"Audio 01","Audio 02","Audio 03","Audio 04","Audio 05"};
+        CD audioCD1=new CD("Audio",audioPlayList);
+        List<CD>CdList1=Arrays.asList(audioCD1);
+
+        return Stream.of(
+                Arguments.of("[loadCDWechseler() by notRunning=CDWechseler ] => shouldThrowAnException", "Case1", cdPlayer1,CdList1,new CDWechselerNotRunningException())
+        );
+    }
 
 
     }