public void Course_TestToStringOverride()
        {
            string name   = "Java";
            Course course = new Course(name);

            Student ivan = new Student("Ivan", 11111);

            course.AddStudent(ivan);

            string expected = "Course name Java; Student Ivan, ID 11111; ";
            string actual   = course.ToString();

            Assert.AreEqual(expected, actual);
        }