public void LeaveCourse()
{
School mySchool = new School();
Course math = new Course();
Student pesho = new Student("Pesho", 10000, mySchool);
Student gosho = new Student("Gosho", 10001, mySchool);
pesho.JointCourse(math);
gosho.JointCourse(math);
pesho.LeaveCourse(math);
Assert.IsTrue(math.Students.Count == 1);
}
public void LeaveCourseOfNull()
{
School mySchool = new School();
Student pesho = new Student("Pesho", 99999, mySchool);
pesho.LeaveCourse(null);
}