根据下面的类图，编写课程Course类和学生Student类。并用题目给出的测试类Test进行测试。不允许改动题目提供的测试类Test代码。Course类说明如下：（1）addStudent()方法用于添加一个选课的学生；（2）dropStudent()方法用于删除一个选课的学生；（3）toStrin()g方法用于返回课程的所有信息，包括课程名称和选课学生。Student类说明如下：（1）toString()方法用于返回学生的信息。（2）equals()方法用于判断两个学生是否为同一个学生。注意equals()方法的参数类型。

public class Course {
    private String courseName;
    private ArrayList<Student> students;

    public Course(String courseName) {
        this.courseName = courseName;
        this.students = new ArrayList<Student>();
    }

    public void addStudent(Student student) {
        students.add(student);
    }

    public void dropStudent(Student student) {
        students.remove(student);
    }

    public ArrayList<Student> getStudents() {
        return students;
    }

    public String toString() {
        return "Course: " + courseName + "\nStudents: " + students.toString();
    }
}

public class Student {
    private String name;

    public Student(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public String toString() {
        return "Student: " + name;
    }

    public boolean equals(Object obj) {
        if (obj instanceof Student) {
            Student student = (Student)obj;
            return name.equals(student.getName());
        }
        return false;
    }
}

测试类Test:

public class Test {
    public static void main(String[] args) {
        Course course = new Course("Java Programming");

        Student s1 = new Student("Alice");
        course.addStudent(s1);

        Student s2 = new Student("Bob");
        course.addStudent(s2);

        System.out.println(course.toString());

        course.dropStudent(s1);

        System.out.println(course.toString());
    }
}

输出结果：

Course: Java Programming
Students: [Student: Alice, Student: Bob]
Course: Java Programming
Students: [Student: Bob]