src/main/java/services/SchoolSystem.java

@@ -60,14 +60,15 @@ public class SchoolSystem {
         return null;
     }
 
-    public void showAllCourses() {
+    public String getAllCoursesDisplay() {
         if (allCourses.isEmpty()) {
-            System.out.println(" No courses available yet.");
+            return " No courses available yet.";
         } else {
-            System.out.println("\n All Available Courses:");
+            StringBuilder sb = new StringBuilder("\n All Available Courses:\n");
             for (int i = 0; i < allCourses.size(); i++) {
-                System.out.println("  " + (i+1) + ". " + allCourses.get(i));
+                sb.append("  ").append(i+1).append(". ").append(allCourses.get(i)).append("\n");
             }
+            return sb.toString();
         }
     }