Method changeToNextCD of CDPlayer tested changing_from_last_to_first CD -> FirstCDShouldBeTaken.

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

@@ -152,13 +152,17 @@ public class CDPlayer implements Device {
             throw new MaxCapacityExceededException();
         }
         cdWechseler.loadOneCD(cd,index);
-        this.loadedCD=cdWechseler.getCDList()[0];
+        this.loadedCD=cdWechseler.getCDList().get(0);
     }
     public void changeToNextCD(){
         if(activeSource.equals("CDDrive")){
             throw new ChangeCDOnlyOnCDWechselerException();
         }
-        this.loadedCD=cdWechseler.getCDList()[1];
+
+        List<CD> CDList = cdWechseler.getCDList();
+        int indexOfLoadedCD=CDList.indexOf(loadedCD);
+        int nextIndex=(indexOfLoadedCD+1)%CDList.size();
+        this.loadedCD=CDList.get(nextIndex);
     }
 
     //Getters, Setters und SupportMethods

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

@@ -4,7 +4,7 @@ import java.util.ArrayList;
 import java.util.List;
 
 public class CDWechseler {
-    private CD[]CDList=new CD[10];
+    private List<CD> CDList=new ArrayList<>();
     private boolean running=false;
 
 
@@ -16,11 +16,11 @@ public class CDWechseler {
         this.running = true;
     }
 
-    public CD[] getCDList() {
+    public List<CD> getCDList() {
         return CDList;
     }
 
-    public void loadOneCD(CD cd,int index){
-        CDList[index]=cd;
+    public void loadOneCD(CD cd, int index){
+        CDList.add(cd);
     }
 }

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

@@ -404,7 +404,7 @@ class CDPlayerTest {
         if(cases.equals("Case3")) {
             _cdPlayer.changePlaySource();
             _cdPlayer.loadCDWechseler(cd,0);
-            CD firstCD=_cdPlayer.getCdWechseler().getCDList()[0];
+            CD firstCD=_cdPlayer.getCdWechseler().getCDList().get(0);
             assertThat(firstCD).describedAs(testName).isNotEqualTo(null);
         }
         if(cases.equals("Case4")) {
@@ -443,21 +443,24 @@ class CDPlayerTest {
         }
         if(cases.equals("Case3")) {
             CD actualCD=_cdPlayer.getCD();
-            System.out.println("loadedCD_id:"+actualCD.getId());
             _cdPlayer.changeToNextCD();
             CD nextCD=_cdPlayer.getCD();
-            System.out.println("nextCD_id:"+nextCD.getId());
-            /*System.out.println("loadedCD_id:"+_cdPlayer.getCD().getId());
-            System.out.println("actualCD_id:"+_cdPlayer.getCdWechseler().getCDList()[0].getId());
-            System.out.println("nextCD_id:"+_cdPlayer.getCdWechseler().getCDList()[1].getId());*/
-            //System.out.println("nextCD_id:"+nextCD.getId());
             assertThat(nextCD.getId()==actualCD.getId()).describedAs(testName).isNotEqualTo(true);
         }
+        if(cases.equals("Case4")) {
+            CD actualCdBefore=_cdPlayer.getCD();
+            for (int i = 0; i <3 ; i++) {
+                _cdPlayer.changeToNextCD();
+            }
+            CD actualCdAfter=_cdPlayer.getCD();
+            assertThat(actualCdBefore.getId()==actualCdAfter.getId()).describedAs(testName).isEqualTo(true);
+        }
     }
     static Stream<Arguments> changeToNextCDData () {
         String[] audioPlayList=new String[]{"Audio 01","Audio 02","Audio 03","Audio 04","Audio 05"};
         CD audioCD1=new CD("Audio","PopMusic",audioPlayList,"XAc20044");
         CD audioCD2=new CD("Audio","RockMusic",audioPlayList,"BLXPP78");
+        CD audioCD3=new CD("Audio","SalsaMusic",audioPlayList,"KKRP118");
 
         CDPlayer cdPlayer1 = new CDPlayer();
 
@@ -465,16 +468,26 @@ class CDPlayerTest {
         cdPlayer2.changePlaySource();
         cdPlayer2.loadCDWechseler(audioCD1,0);
         cdPlayer2.loadCDWechseler(audioCD2,1);
+        cdPlayer2.loadCDWechseler(audioCD3,2);
+
 
         CDPlayer cdPlayer3 = new CDPlayer();
         cdPlayer3.changePlaySource();
         cdPlayer3.loadCDWechseler(audioCD1,0);
         cdPlayer3.loadCDWechseler(audioCD2,1);
+        cdPlayer3.loadCDWechseler(audioCD3,2);
+
+        CDPlayer cdPlayer4 = new CDPlayer();
+        cdPlayer4.changePlaySource();
+        cdPlayer4.loadCDWechseler(audioCD1,0);
+        cdPlayer4.loadCDWechseler(audioCD2,1);
+        cdPlayer4.loadCDWechseler(audioCD3,2);
 
         return Stream.of(
                 Arguments.of("[changeToNextCD() by CDWechselerNotSelected ] => shouldThrowAnException", "Case1", cdPlayer1,new ChangeCDOnlyOnCDWechselerException()),
                 Arguments.of("[changeToNextCD()  checking the effect ] => loadedCDShouldNotReturnNull", "Case2", cdPlayer2,null),
-                Arguments.of("[changeToNextCD()  checking the effect 2 ] => loadedCDShouldNotHaveTheSameIdAsPrev", "Case3", cdPlayer3,null)
+                Arguments.of("[changeToNextCD()  checking the effect 2 ] => loadedCDShouldNotHaveTheSameIdAsPrev", "Case3", cdPlayer3,null),
+                Arguments.of("[3x changeToNextCD()  changing from last to first CD] => FirstCDShouldBeTaken", "Case4", cdPlayer4,null)
         );
     }