Fixed assignment manager to pass some tests, scanner is not yet implemented fully

src/main/java/hhn/temp/project/AssignmentManager.java

@@ -27,6 +27,9 @@ public class AssignmentManager {
         return workerIdCounter;
     }
     public void removeWorker(int workerId) {
+        if (!workerMap.containsKey(workerId)) {
+            throw new IllegalArgumentException("WorkerId must exist in order to remove it");
+        }
         workerMap.remove(workerId);
     }
     public int addTask(int workerId, String name, String description) {
@@ -74,5 +77,8 @@ public class AssignmentManager {
         Task task = taskMap.get(taskId);
         task.setTaskState(TaskState.IN_PROGRESS);
     }
+    public UserCommands getUserCommands() {
+        return userInterface;
+    }
 
 }