public void Test_GetStudents_ReturnStudentsInCourse()
        {
            //Arrange
            Course testCourse = new Course("Running", "PE901");

            testCourse.Save();

            DateTime enrollmentDate = new DateTime(1795, 04, 13);

            Student firstStudent  = new Student("Rebecca", enrollmentDate);
            Student secondStudent = new Student("Julia", enrollmentDate);
            Student thirdStudent  = new Student("Claire", enrollmentDate);


            //Act
            firstStudent.Save();
            secondStudent.Save();
            thirdStudent.Save();

            testCourse.AddStudent(firstStudent);
            testCourse.AddStudent(secondStudent);
            testCourse.AddStudent(thirdStudent);

            //Assert
            List <Student> expectedResult = new List <Student> {
                firstStudent, secondStudent, thirdStudent
            };
            List <Student> actualResult = testCourse.GetStudents();

            Assert.Equal(expectedResult, actualResult);
        }
        public void Test_AddStudent_AddsStudentToCourse()
        {
            //Arrange
            firstCourse.Save();

            DateTime enrollmentDate = new DateTime(1795, 04, 13);

            Student firstStudent  = new Student("Rebecca", enrollmentDate);
            Student secondStudent = new Student("Julia", enrollmentDate);

            firstStudent.Save();
            secondStudent.Save();

            //Act
            firstCourse.AddStudent(firstStudent);
            firstCourse.AddStudent(secondStudent);

            List <Student> actualResult   = firstCourse.GetStudents();
            List <Student> expectedResult = new List <Student> {
                firstStudent, secondStudent
            };
        }