编写一个图书类（Book）和一个图书测试类（TestBook）

好的，我们可以创建一个简单的图书类（Book）作为基础实体，并编写一个测试类（TestBook）来进行相关的功能测试。

**图书类（Book.java）：**

public class Book {
    private String title;
    private String author;
    private int publicationYear;

    public Book(String title, String author, int publicationYear) {
        this.title = title;
        this.author = author;
        this.publicationYear = publicationYear;
    }

    // getter and setter methods
    public String getTitle() { return title; }
    public void setTitle(String title) { this.title = title; }
    
    public String getAuthor() { return author; }
    public void setAuthor(String author) { this.author = author; }

    public int getPublicationYear() { return publicationYear; }
    public void setPublicationYear(int publicationYear) { this.publicationYear = publicationYear; }

    @Override
    public String toString() {
        return "Title: " + title + ", Author: " + author + ", Year: " + publicationYear;
    }
}

**图书测试类（TestBook.java）：**

import org.junit.Test;

public class TestBook {
    @Test
    public void testBookProperties() {
        Book book1 = new Book("The Catcher in the Rye", "J.D. Salinger", 1951);
        System.out.println(book1); // 测试标题、作者和年份是否正确显示

        // 检查默认构造函数
        Book book2 = new Book();
        assert book2.getTitle().equals("");
        
        // 测试setter和getter方法
        book2.setTitle("To Kill a Mockingbird");
        book2.setAuthor("Harper Lee");
        book2.setPublicationYear(1960);
        System.out.println(book2);
    }
}

在这个例子中，`Book` 类代表基本的图书信息，而 `TestBook` 类则是用来测试 `Book` 类的各种方法是否正常工作的单元测试类。`TestBook` 中的 `testBookProperties` 方法用于验证书名、作者和出版年份属性的设置和获取功能。