TDD练习

今天在收集中看到一道面试题，网络引用是：http://www.iteye.com/topic/954262。题是这样的：

 

如何编程实现：输入M,N两个数，从1至N开始循环数数，每数到M输出该数值，直至全部输出。例如M是3，N是20，那么相当有20个人，1，2，3循环报数，数到3的就打印出他的序号，直到所有这20个数全部输出为止。

题目摘自：http://jerval.iteye.com/blog/1068563

尝试使用TDD编写产品代码，在实现时发现测试覆盖率不够；有哪位大虾能说说测试粒度该怎样规划？

测试代码：

public class DeliverTest {
    @Test
    public void onePlayer() throws Exception {
        Deliver deliver = new Deliver(1);
        assertArrayEquals(new int[]{1}, deliver.play(2));
        assertArrayEquals(new int[]{1}, deliver.play(-1));
    }

    @Test
    public void twoPlayers() throws Exception {
        Deliver deliver = new Deliver(2);
        assertArrayEquals(new int[]{2, 1}, deliver.play(2));
        assertArrayEquals(new int[]{1,2},deliver.play(1));
    }

    @Test
    public void manyPlayers() throws Exception {
        Deliver deliver=new Deliver(20);
        System.out.println(Arrays.toString(deliver.play(3)));
    }
}

 代码：

public class Deliver {
    public static final int FIRST_PLAYER = 0;
    public static final int FIRST_NUMBER = 1;
    private int[] evicted;
    private int evictPos;
    private int repeat;
    private int[] players;
    private int current;

    public Deliver(int count) {
        evicted = new int[count];
    }

    private void reInit(int repeat) {
        evictPos = 0;
        this.repeat = repeat;
        players = createPlayers();
        current = FIRST_PLAYER;
    }

    private int[] createPlayers() {
        int count = evicted.length;
        int[] players = new int[count];
        for (int k = 0; k < count; k++)
            players[k] = k + FIRST_NUMBER;
        return players;
    }

    public int[] play(int repeat) {
        reInit(repeat);
        replay();
        return evicted;
    }

    private void replay() {
        talk(FIRST_NUMBER);
    }

    private void talk(int numberOff) {
        if (shouldEvict(numberOff)) {
            evict();
            return;
        }
        deliver(numberOff);
    }

    private boolean shouldEvict(int numberOff) {
        return numberOff >= repeat;
    }

    private void evict() {
        evicted[evictPos++] = players[current];
        if (isOnePlayerOnly())
            return;
        players = remove(current);
        replay();
    }

    private boolean isOnePlayerOnly() {
        return players.length == 1;
    }

    private int[] remove(int index) {
        int[] remaining = new int[players.length - 1];
        int next = index + 1;
        System.arraycopy(players, FIRST_PLAYER, remaining, FIRST_PLAYER, index);
        System.arraycopy(players, next, remaining, index, players.length - next);
        return remaining;
    }

    private void deliver(int numberOff) {
        current = nextPlayer();
        talk(numberOff + 1);
    }

    private int nextPlayer() {
        int next = current + 1;
        return next >= players.length ? FIRST_PLAYER : next;
    }

}

 

评论

3 楼 oray2011 2011-06-03  

抛出异常的爱 写道

引用

@Test  
    public void manyPlayers() throws Exception {  
        Deliver deliver=new Deliver(20);  
        System.out.println(Arrays.toString(deliver.play(3)));  
    } 

这个叫测试么?

这不是测试，这是这个问题的答案~！虽然可读性比较强，但我觉得这个测试是有问题的，测试粒度太大；我应该如何着手编写粒度适中的测试，希望大家给出各自的意见~！

2 楼 william_ai 2011-06-03  

人肉测试。。。。

1 楼 抛出异常的爱 2011-06-03  

引用

@Test  
    public void manyPlayers() throws Exception {  
        Deliver deliver=new Deliver(20);  
        System.out.println(Arrays.toString(deliver.play(3)));  
    } 

这个叫测试么?