3th

src/com/university/Department.java

@@ -12,6 +12,7 @@ public class Department {
         this.name=name;
         students=new ArrayList<Student>();
         courses=new ArrayList<Course>();
+        professors=new ArrayList<Professor>();
     }
 
     public String getName(){

src/test/DepartmentTest.java

@@ -7,36 +7,54 @@ import com.university.Student;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 
+import java.util.ArrayList;
+
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 public class DepartmentTest {
     static Department department;
-    static Student student;
-    static Course course;
-    static Professor professor;
-
+    static Student student,s2;
+    static Course course,c2;
+    static Professor professor,p2;
+    static ArrayList<Course>courses;
+    static ArrayList<Professor>professors;
+    static ArrayList<Student>students;
     @BeforeAll
     public static void creatStudent()
     {
+        courses=new ArrayList<>();
+        professors=new ArrayList<>();
+        students=new ArrayList<>();
         department=new Department("abc");
         professor=new Professor(department,"kz");
         course=new Course("123","math",department,professor,3);
         student=new Student("ali","1234","abc",department);
+        s2=new Student("Mohammad","124","b",new Department("aa"));
         department.addCourse(course);
         department.addProfessor(professor);
         department.addStudent(student);
+        department.addStudent(s2);
+        for(int i=0;i<department.getStudents().size();i++)
+            students.add(department.getStudents().get(i));
+        for(int j=0;j<department.getProfessors().size();j++)
+            professors.add(department.getProfessors().get(j));
+        for(int z=0;z<department.getCourses().size();z++)
+            courses.add(department.getCourses().get(z));
     }
     @Test
     public void Test(){
         assertEquals("abc",department.getName());
-        assertEquals(professor,department.getProfessors().get(0));
-        assertEquals(course,department.getCourses().get(0));
-        assertEquals(student,department.getStudents().get(0));
+        assertEquals(professors,department.getProfessors());
+        assertEquals(courses,department.getCourses());
+        assertEquals(students,department.getStudents());
         department.removeCourse(course);
+        courses.remove(course);
         department.removeProfessor(professor);
+        professors.remove(professor);
         department.removeStudent(student);
-        assertEquals(0,department.getProfessors().get(0));
-        assertEquals(0,department.getCourses().get(0));
-        assertEquals(0,department.getStudents().get(0));
+        students.remove(student);
+        assertEquals(professors,department.getProfessors());
+        assertEquals(courses,department.getCourses());
+        assertEquals(students,department.getStudents());
     }
 }