Method loadCDWechseler of CDPlayer tested on leadingFirstCD -> CDListOfCDWechselerShouldHaveLength1.

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

@@ -148,6 +148,7 @@ public class CDPlayer implements Device {
         if(!(this.supportedFormats.contains(cd.getFormat()))){
             throw new FormatNotSupportedException();
         }
+        cdWechseler.loadOneCD(cd);
     }
 
     //Getters, Setters und SupportMethods
@@ -197,6 +198,7 @@ public class CDPlayer implements Device {
         return this.loadedCD;
     }
 
-
-
+    public CDWechseler getCdWechseler() {
+        return cdWechseler;
+    }
 }

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

@@ -1,9 +1,10 @@
 package device.cdPlayer;
 
+import java.util.ArrayList;
 import java.util.List;
 
 public class CDWechseler {
-    private List<CD>CDList;
+    private List<CD>CDList=new ArrayList<>();
     private boolean running=false;
 
 
@@ -15,5 +16,11 @@ public class CDWechseler {
         this.running = true;
     }
 
+    public List<CD> getCDList() {
+        return CDList;
+    }
 
+    public void loadOneCD(CD cd){
+        CDList.add(cd);
+    }
 }

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

@@ -401,6 +401,12 @@ class CDPlayerTest {
             Exception newException = assertThrows(exception.getClass(), () -> _cdPlayer.loadCDWechseler(cd));
             assertEquals(FormatNotSupportedException.class, newException.getClass());
         }
+        if(cases.equals("Case3")) {
+            _cdPlayer.changePlaySource();
+            _cdPlayer.loadCDWechseler(cd);
+            int length=_cdPlayer.getCdWechseler().getCDList().size();
+            assertThat(length).describedAs(testName).isEqualTo(1);
+        }
     }
     static Stream<Arguments> loadCDWechselerData () {
         CDPlayer cdPlayer1 = new CDPlayer();
@@ -411,7 +417,8 @@ class CDPlayerTest {
         CD DVD=new CD("DVD",videoPlayList);
         return Stream.of(
                 Arguments.of("[loadCDWechseler() by notRunning=CDWechseler ] => shouldThrowAnException", "Case1", cdPlayer1,audioCD1,new CDWechselerNotRunningException()),
-                Arguments.of("[loadCDWechseler() by WrongCDFormat ] => shouldThrowAnException", "Case2", cdPlayer1,DVD,new FormatNotSupportedException())
+                Arguments.of("[loadCDWechseler() by WrongCDFormat ] => shouldThrowAnException", "Case2", cdPlayer1,DVD,new FormatNotSupportedException()),
+                Arguments.of("[loadCDWechseler() by leadingFirstCD ] => CDListOfCDWechselerShouldHaveLength1", "Case3", cdPlayer1,audioCD1,null)
         );
     }